My first upgrade on my new 08 C4S was GIAC ECU. I decided to go with them, since they have a 30 days return policy. Its been 2 days, so far not too impressed. I didn't get the ECU expecting a massive hp/torque increase, however I would expect some improvement, but nothing much so far. I'll give it few more days........ I have heard good review from Softronics, they claim close to 30hp, which sounds a bit too high. I was looking at Plenum, however I'm still not sure, how a Y vs T design could provide so much power. As for the intake, it seems all it does is make the car sound nicer however no real gain.............Any personal experience/feedback is appreciated.
Thanks

 

I had GIAC on my first 997, did nothing for gains IMO.

Save your money, software on a NA vehicle will not give you any significant gains.

 

I've learned that the major adjustment on all these flash solutions is about a 3 degree advancement in timing. I think that would simply remove the safety margin of putting in the wrong fuel, right? And it "should" result in some level of performance gain. How much is debatable...
I'm seriously looking at Softronics and that will probably be my next MOD. I'll let you all know how that goes.

 

Softronics is the way to go. I had it in my 07 and at the track I could tell a difference. On the street the car was more livley in the mid range power band.

 

I've been running GIAC software for about 50K miles on my 997S. I've dyno tested endlessly and have never failed to see gains. However, I don't think any vendor's software will make much difference (safely) without some adjustments to intake and exhaust.

 

Darren, with all due respect, your car is a little different then most 997's. I am sure your gains are due to the VF unit, and not the software.

 

True, sir. However, I was running GIAC software with more typical intake and exhaust mods at least a year before I added the VFE kit. The gains on the real dyno and butt dyno were significant. But I never did an ECU flash without intake and exhaust mods. I just don't think any vendor will provide signficiant performance improvements without improving intake and exhaust flow. IMHO.

Even the VF kit wouldn't provide as much improvement without adjusting the ECU, and GIAC has done a good job all through my phases of modding.

 

My GIAC flash was with an EVOMS headers and mufflers. Did you have hi flow cats? I feel that the AWE cats that I installed were a bigger gain then all the other pieces (headers, mufflers, and software) combined.

BTW, I am way too young to be called sir

 

My cat mods came later than the VFE kit. I've tinkered incrementally and gone back and forth on a few mods, so it's hard for me to pinpoint exactly what mod gave me what gain after my initial set. It's like asking a crazy person, "so at what point exactly did you go insane?"

BTW, the term "sir" is one of respect, not one of age. Stay young.

 

I built things up in pieces on my car as well. I found thatit allowed me to notice what provided gains, and what didn't. I think the only power gains were from hi flow cats. Short of going forced induction NA gains are minimal at best, and doing it over again, I would spend the money on suspension again, and leave the engine alone.

 

I was thinking about installing just the AWE mufflers, cats and tips. Will this work as well without adding ECU software?

 

I had the GIAC Software, Evo Intake and AWE Muffler installed a couple of weeks ago and noticed a bit of improvement in the butt dyno, not quite the 30hp the "combo" claimed. I had the software and intake removed the other day because I am taking my car in for some warranty work and truthfully the car feels just as good. I might take GIAC up on the 30 day refund....

 

You will be fine without software. I would do headers instead of mufflers, the hi flow cats will make it loud enough, I switched back to my PSE as the full system was way to loud for my situation.

 

What about Plenum?? I hear good things, but I've also heard it doesn't do much. As for intake, it seems that all it does is make the car sound better, but not real gains?

 

There is a lot of threads in the 997 forum about the Plenum including dyno charts.

Most results haven't been favorable, I don't have one, and feel that it is not providing the gains that they claim.