Here's the deal. Since you need fairly high boost pressure to achieve your stated 300 h.p. minimum you need to go with sequential turbos or a single supercharger. The value in a supercharger is that they are available for your 2.8. The stacked turbos will be hard to fit in the space you have. You will need to chip your engine control system to allow for and allow the added horsepower. I would go supercharger if it was mine. You can do it for about $4000 all in and you will be able to get somewhere around 400 h.p. Now as to whether the engine can take that much stress I would guess it probably can for short periods but eventually you will blow the bottom or the top. I bet the bottom leaves first. Good luck which ever you decide. As an alternative you can drop in a nice used twin turbo 2.7 and chip it for about that same h.p. I haven't read the whole thread so if I covered ground that has already been discussed I apologize. If you decide to stack turbos go KO3 into KO4 and throw the fuel to it.

 

Well the supercharger sounds good i meab 400 hp is nice. But u r right for a cheaper price u can chip a 2.7 twin turbo to get the same power. I just dont want to sell my car.
anyway ill see weather i turbo charge and spend the extra money, supercharge it or sell it and get 2.7.
but thank you for your advice something to think about.

 

Keep the car but replace the 2.8 with A 2.7 twin turbo. Look for a used 2.7 on the internet or at a local pull-a-part.

 

Yeh hi.
I have a 2001 audi a6 2.8 quattro,
She runs around 8s-8.5s 0-100 km/h and i wont to know how to make it faster and rev higher.
Any suggestions?