I haved owned several exhausts for my turbo, five now in total and thankfully my last. I LOVE LOVE LOVE my 2.5 quiet x-cellerator exhaust I got from John at speedtech.
Personally I had the crazy loud droney exhausts, the boring stock (but drone free) exhaust note as well as some models in between. But nothing sounds as sweet as this cross flow. Its hard to explain its just right, not too loud as to annoy my neighbors but a monster when "I" want it to be.
When I first talked with John I was slightly apprehensive as I didn't want to make the same mistake again as I was waiting for the elusive used ep2 quiet to come up for sale. But thankfully John put my mind at ease and made me feel comfortable enough to pull the trigger on another exhaust system. As I only had youtube clips to go by and not ever hearing one in person, for me this was a big leap of faith. But john's communication and how passionately he spoke of it (as well as other happy members than run it I pm'ed) loosened my purse strings so to speak.
The first time I started it up in the garage it was deep and throaty. Plus hearing the turbos whistle for the first time was awesome. It quickly mellowed out to a nice rumble, louder than stock at idle but by no means annoying.
My first drive windows closed, it sounds unique, like no other exhaust I have had (the youtube videos help but do not do it justice) there is some drone but its in a very small band and by FAR less than anything else I had, easily liveable and I'm kind of a whinny little ***** when it comes to drone, I hate it. I am confident enough in saying that your passengers or wife wont mind it either. Its not over powering in the cabin of the car so handsfree cell phone calls are not an issue and the factory stereo can easily be enjoyed. But why would you listen to music when you can open the windows and mat the gas!
Windows open, drone is all but non existant, and you can really enjoy the sweet tone the xflow makes. If I find myself in a tunnel, I cant resist opening it up. Never did that before.
John was excellent to deal with, super fast email return(and there was alot of them) He even called me on the day I installed it to make sure everything went smoothly and we ended up BSing for an hour about cars. Who does this? I bet if I asked him to fly out to the west coast and install it for me he would. Highly, highly recommend anything he sells as he definetly stands behind it and gave above and beyond customer service. John thank you for everything.
If you are on the fence, or just looking for something you'll never sell till you trade the car in, THIS IS IT!!
Don't take my word for it look up other posts, I'm just another happy customer. Keep up the good work John, you deserve all the praise you get.

 

Hi Scott,

I'm so pleased to read this review, as I had not heard from you for a few weeks and I was wondering how you liked it - I was actually about to email you as a follow-up. I had a sense you were going to be extremely tough to please, but did feel confident I had recommended the right exhaust for you and that you would truly enjoy the unique sweet sound of our internal X-Flow design. After reading your impressions, I can relax knowing you are loving it. I was hoping you would have the same ownership experience as I - that is I look forward to driving the car every time I have a reason to and no matter how long the drive, I never tire of the 2.5 X-cellerator X-flow exhaust sound! It's always a pleasure rev it out and listen or just cruise at low RPM enjoying the stereo when in the mood. I too have had other exhausts that have made me not want to drive the car at certain times, as I did not feel like experiencing the drone - that's never a concern with our 2.5...in fact, after over 3 years with this system on my personal car, I still get excited to drive the car and hear the exhaust every time! I may be a little biased, but in all honesty, I think you made a very wise choice...and I thank you so much for your business and the kind words!

 

No problem John, glad to spread the word with others about a great product and a happy customer.

 

HI,,What cats did you go with??

 

100 cell as per johns advice. The turbo whistle is awesome and seems to flow really well. At least seat of the pants feel.

 

Great.......Enjoy...

 

Can hardly wait for my Speedtech 3'' catless system to arrive!

 

You mentioned a "slight" drone - what RPM range does it happen at?

 

Slider I'd say it's in the rpm range 2400-2500 and only under light throttle input with the windows up. Its hard to be exact as it is very narrow. If you move through that range quickly or just drive with the windows down or just listen to your stereo at a reasonable level (what I mean by reasonable is that conversation is still easy to have in the cabin with the music playing) it won't be an issue. Where I live is we're the mountains meet the ocean so it's very hilly which is drone central and traffic here is awful so I figure most times if I can't go fast I'll conserve as much gas as possible as its stupid expensive here as well. Which means I spend all my time in a high gear and low rpm with little throttle input. I actually find right at 2k it's great, yes it's louder in the cabin than stock but not annoying to myself, my friends or my wife. I can't say that about any of the other systems I had outside of stock and we all know how boring they sound and how restrictive they are.
It's MUCH better than the three inch RPI and the 2.5 fabspeed gen3 twin can (which was too loud and didnt sound nearly as cool) I personal won't want it any louder or quieter, yes there is minimal drone in the tiny rpm range mention but it's very easy to avoid and it's really only noticeable under slight throttle input with the windows up. Far superior to any other system I have heard or owned.
As well as I have had it now for a little while I find it's getting even better, more settled in and mellow but still barks when I hit it.
I have what John considers to be the best setup for flow, still hearing the turbo whistle and least amount of drone, that being 100 cell 2.5 quiet muffler and single slant cut tips. And if your sound qualifications are similar to mine I too would recommend this setup best of both worlds. The tips to be honest were not my first choice, but they have truely really grown on me and fit the tip opening in the bumper nicely and look pretty aggressive too. They do stick out 1/2 inch past the bumper cover which I actually always liked not too far just enough to say "that's right, I'm not stock".
If anybody has any questions please feel free to ask. It got me off the exhaust roller coaster and its finally right. Just awesome.
My car is a k16 epl stage 2 flashed 6 speed car.

 

Thanks for the extra info. I have the older SpeedTech 3-inch now and the drone pretty loud and is right at 2K which is cruising highway speed here. The wife won't go on long rides with me since I put on this exhaust. Moving the drone band up to 2400 would be very helpful. So, who has a used 2.5 quiet x-cellerator they want to let me try?

 

If you ever make it over to Vancouver (port Coquitlam exactly) I'll let you try mine out. My wife is... How do I put this nicely... Let's say difficult, and she doesn't mind it at all. She notices that yes it's louder than stock but even today she's "let's take your car to the malls shopping" and I'm like "hell no, people are idiots here especially during Xmas shopping" stalls are too small they've been putting rock salt everywhere. Not worth it. So we took hers

 

Slider,

If you have our 3.0 system, you can purchase a just a 2.5 muffler and 2.5 tips, to convert your system to a 2.5 "quiet". It will make a big difference in the sound inside the cabin and I'm pretty sure your wife (and you) would be thrilled with the change.

 

Any love for the Cayennes John (955/957), '08 GTS to be specific? :-)

 

Hi Jay,

Yes, we have the love :-) We just recently decided to develop this model, but it will be a litle while. Designing and testing these systems takes a bit of time...

 

Very cool - it'll be interesting to see what you come up with! Thanks!