For my next car i am considering an B5 A4, B5 S4, B6 A4, or B6 S4. All are avant, quattro, manual. Which one of these engines would be the most realiable DD while still making 400chp? All I am trying to determine which would require the least maint. and least likely to fail. Obviously there would be other supporting mods (clutch, tranny, suspension, brakes) but I am only concerned with the engines at this point.

 

B5 s4 would be the easiest to mod but expensive to maintain. a4 b6 would be pretty expensive to make fast, but a bit cheaper in maintance.
b6 s4 you wont get 400hp, unless you supercharge it.

 

Depends how much you wanna spend. Each one has its pro's and con's, but they can all reach your goal. Most of your choices ^ are turbo charged except the B6 S4. Where you looking for turbocharged?

 

im not really partial to turbo charging but like you said thats more than likely what would get me there. Im just wondering which one will be most realiable around 400chp. i know the s4 will be harder to work on but an a4 would require a bigger turbo

 

Any of the following cars (except of b6 s4) would require a bigger turbo(s).
Are u looking for 400hp at the crank or 400whp?

 

They didn't make a B6 S4 Avant in the states did they?

A 1.8t will get you 400chp with a 2871r and supporting mods. A K04 S4 will be a little over 400 and the B6 S4 can be FI'd. Be more specific on budget blah blah blah...

 

They do have b6 s4 Avant

 

Really? i know for the B6 there's the sedan and convertible. There must not be many avants in our area.