the 01 turbo is the same houseing but the fins are cut dif. thats why when you see the chip # for the 01 they are more than other years.

 

they never put vvt on the b5. it was only done on the vw side never audi

 

ok so now we have two different views. the turbo isn't the same right? that's my guess. it's all a ko3 turbo. i'm pretty sure i agree with what was said about the different ecu

 

pre 2001 all turbos are ko3 2001 and above they all come with the ko3 sport

 

No, VVT is on the 2001 A4. It was done on the VWs and Audis.

The red flag actually also signifies the 2001.5 model, which had the ko3 sport, instead of the regular ko3.

 

Do you mean the red "T" because the 2001 i am looking at has the red "T" and i was looking for a way to tell if it is the sport tuned one

 

No K03 sport was original equipment for an A4. The 01 has the K03-29 "J" (sometimes seen as "JC") model K03 turbo. The K03 sport was only available from the factory for transverse engines on the Golf, Jetta, A3, and New Beetle. The "J" model K03 was upgraded for reliability not performance. You can get a K03 sport for your A4 but not from the factory.

K03 part number for pre 01 turbo- 058 145 703 L
K03 part number for post 01 turbo- 058 145 703 J
K03 sport part number- 06A 145 704 S

This link will explain.