Is this worth $3100?
3800 performance turbo kit

The page gives info about use on a GT, and sells a kit for the GTP, but didnt really say what gains a GTP would have. Any idea what I could expect? Would it be the same as the GT because you are killing the SC?

The GT engine would be a little stronger because it is higher compression. But comparable gains, yes.

Power gains between the GT and GTP are negligible. The GTP's have lower compression yes, but that just means you have to run more boost for the same hp gain.

Also, the GTP's have stronger rods and pistons, an advantage over the GT. Not to mention the HD diff.

nawwww not worth it, go with one of zzps setups z3 or z7 setup better and cheaper PERIOD

Also turbos are more efficient at higher boost levels than lower ones.

The Cartuning turbo kit is pretty good but I would say go with ZZP's kit it is a little more up to date and has better customer service .If your handy welding and such you could put a turbo kit together yourself cheaper.

The z3 kit is a crappy version of the CT kit. They copied CT with the way the wastegate mounts to the rear PEM. The turbo is Borg Warner which is good but the kit runs open dump on the wastegate. Seems lazy to me...

Look on ClubGP There are 3 Stattama I/C kits going for around 3k full kits. I bought my CT I/C kit really cheap lol.

The CT kit has one big flaw and that is where the wastegate is mounted. This flaw was copied to the Z3 kit too... If you plan on buying the new CT kit at least get the pt-61 turbo upgrade. Also having the I/C makes a huge difference power wise.

Z7 - CT kit are comparable.

I will say this the z7 kit has a better wastegate layout. ZZP allows you to run both front and rear plogs. The ct kit allows for a front Plog but not the rear because of the way they mounted the wastegate.

The z7 kit comes with the t62-1 turbonetics turbo. Personally I can't stand turbonetics because there customer service is horrible and there warranties are pathetic. Many have had issues with oil feed and return with t62-1 and the t67 turbonetics turbos. Don't get me wrong the higher end turbonetics are nice like the GTK turbo which is ridiculous but $$$$$.

The CT kit comes with the PT-61 precision tuning turbo much better turbo in general and better company IMO.

Stattama Kit owns all. All I have to say lol. It comes with the PT67 as the base turbo which is a great turbo. Also allows for larger turbos etc. Front and rear plogs included better t4 flange and option for the oversized spearco I/C.

Each kit allows for larger turbos to be installed.