the flange as where the manifold mates with the turbo. The ko3 style flange has just a tiny hole that doesnt flow very well. The t25 is a bigger, a t3 is even bigger and the t4 is the biggest. T25 housing (exhuast housing/turbine) are good for small turbos and t3 are better for slightly larger to rather big turbos. You wont need a t4 unless you plan on a drag car and 700+whp.

 

I want to match this turbo with the atp high flow manifold and a test pipe will this be a good idea?

 

its not a bad idea, ill just say that

but i will also say don't get a 71r or bigger if your keeping your tranny. gtrs should be good for you.

 

it would, but then you just completly wasted the so called money you would of saved buying a kit in the first place. With about the same spool and power at far less boost, why not just get a t3t4 50trim with a .48 turbine housing? You should be right at 300whp with 20psi and since its a journal bearing turbo, the power curve is much smoother and safer for both rods and tip than a gt turbo. Or if you want faster spool and a little less power, a t3s60 would be a good choice. The only elim i like is the gt2x. It fine with the stock manifold and flange, spools super fast and makes good power. Just let it cool after shutdown and you wont have any worries with it.

 

Would a company like Unitronic be able to give me a ECU Upgrade for the Gt2x Kit or the T3/T4? If you know, what numbers do most people reach with the Gt2x kit?

 

Uni or revo should have tunes for both. Dont know who makes a better 2000 tune. But the gt2x typically makes 240fwhp and 260tq. This is the less than ideal transverse setup. A A4 should see close to the same #'s but in awd. This turbo is basically made to be like the ko4-20 from a 225TT. Search Audizine for some dynos.

 

there are about half a dozen TIP GTRSs on audizine.... i would put a GTRS before a k04 on a tip because of the gradual torque curve of the GTRS compared the vicious spike on the k04...

you are also going to need full exhaust and FMIC...

www.ecodetuning.com has some nice kits that include the REVo software... i know its the best for b6s but i dont know about b5s

 

Uni has a better tune for the B5, Revo has a better tune for the B6.

 

Should I still put a high flow manifold and test pipe with the Gt2x or don't bother the cost is not an issue? Also Should I go with bigger injectors or anything besides a Unitronic tune?

 

the manifold should be fine, the tp should be done. 380 or 440cc would be plenty for the gt2x