Help On talon tsi

Recently I purchased a 92 tsi from a co-worker for 200$.(he had no interest in the car whatsoever, and couldnt put the wrench time, or money into the tranny) Great car, just had to replace the transmission. So after that, installed a racing clutch and she ran like a beaut. A month or two down the road, I had a full 3 inch exhaust put on the car from the cats and it ran fine for another month.Then it started to sputter around 4 grand and would struggle then would run fine to 6 grand. Next the turbo went and I replaced it with a 16g evo turbo. After I replaced it I thought my problem was solved. Well I was wrong and now it wont run above 4 grand.
So I did a couple of the small fix her ups to see if that was the problem, but it was a waste of about 500$. I love the car, and just wondering if anyone else had this problem.

Thanks.

maybe I didnt word it right, or include enough info... but thanks for the help!!!! I know exactly where to go next time I need help on my ride......

Probly could include some more info, But most of the time people have a close answer right quick.

I dont think it has to do with the exaust because that would only effect you on the low end. Its probly in the eletrical, What did you replace?

Have you checked your plugs/wires? Checked the cylinder compression? Any check-engine-lights?

Yeah I changed/replaced the plugs/ wires, fuel pressure regulator, checked the turbo for a leak, along with the fuel line, put on a new coil pack... No CEL... My best guess would be the ECU but wanted to see if there was any advice from you guys before I dropped the money on it.

Thanks for replying with ideas and help :)

Does it sputter at all rpm's or just doesnt go above 4000

Now it wont go above 4. . .

did you check your MAS? go to www.vfaq.com (http://www.vfaq.com) and test the IAT sensor to see if its working properly, mine on my MAS was fucked up so i replaced the MAS and it works just fine now!

Was there oil on the plugs