I just picked up my 1999.5 a4 Quattro Avant 1.8T and I've been doing a bit of upgrades and repairs on it already (timing belt, axel, tie end rods, coolant) and Apr Stage 1 chip. I'm curious if I can replace the K03 with a K04 and make no other mods to the car. Will the car run correctly with the different turbo with a Stage 1 chip designed for the K03? I seriously searched for a while on this topic and I found very little. Anyone know?

 

with a k04 upgrade, your car will be fine but will not live to it's full potential without a k04 tune. it is recommended that you do upgrade the file as soon as you can because your car will not run 100% smoothly.

 

I have a K04 and still have my Dahlback chip for the K03, haven't had the money for a new chip, runs just fine. I got the K04 about 2 years ago.

 

Did it make a difference, enough to warrant purchasing one? BTW what did you do with your lower grills? It looks good.

 

The K04 is a gateway drug, the power you get from it will make you happy for 6 months then you will want a BT. Yes it is worth it, but everyone after getting one wants a bigger turbo. If I were to do it again, I would wait and save up and get a 2871r.

Thanks too. The lower grills are 1/4" perforated aluminum. Some people say it looks like a GMC, but I really like it.