99 C2 are ALL cable throttle, 99 C4 is Electronic throttle.

On my 99 C4, i did a complete engine rebuild and a Vivid Racing VR996CT Kit. 5.5psi I make 470hp and 430 TQ at the crank. Very happy with the car and the power.

Your only choices are a supercharger kit or do a whole engine swap with a cool engine like a 3.6 or 3.8 Cup Car or some guys now are dropping LS V8's in them...

 

I say turbo it!!! Someone's gotta do it!

 

what are your plans for the car? what are you looking to accomplish with more power? the 3.4L is a good engine, but it has its limitations, especially when it comes to boost. sure you rebuild it, change the pistons for boost, new cams, some head work, new bearings ect. but thats a lot of time, and a lot of money, likely more then you would spend on a 996TT.

you can really wake up a 3.4L 996 with some suspension mods, exhaust, LSD, clutch, lighter flywheel, and brakes.

 

Do it and post up results

 

996 3.4 engine has the weakest cylinder walls of any watercooled flat 6 cyl.
So 1st step should be to sleeve block with bigger, thicker cyl sleeves to add 3mm to the bore & give you 3.6Litres.

This will add power,reliability,resale value & requires no "tuning". For more info see this thread: https://www.6speedonline.com/forums/...gine-sale.html

 

I will say I dont know much about this particular application but I will say that the non-turbo 996's look so much better to me that I'd consider doing a 996 and turbo'ing it with a 10-13k kit rather than end up with a turbo on looks alone. I hate the huge vents and the awful spoiler. To me the 6GT3 is probably the sweet spot on looks vs power. But the lack of a back seat kills it for me (wife factor)

 

If you are not doing any of the work yourself it is just to cost prohibitive and tuning is the hard part finding someone to tune the onboard computer or if you use a piggy back system it is still difficult at best. VF engineering used to sell a bolt on SC kit and still might that would be your best bet in my opinion or just get a Turbo.

 

There's a lot of room in the rear fenders to put some turbos.

Since the 3.4 can't take much boost in stock form, go for some small turbos that spool fast.

You might be able to get away without an intercooler since the boost levels are so low. Otherwise some air/water intercoolers would allow you to mount them inboard on the car.

. . . or just go LSx.