I am considering changing to the A6 line (A4 too small for my taste), but want power and handling of the A4, and turbo.

I am looking at:

- A6 2.7T and upgrade the turbos (to RS4 level)

Also: S6 with upgrade to twin turbo. How difficult is it to upgrade the 4.2 engine in the S6 to twin turbo RS6 level?

 

The topic of turbo charging the S6 4.2 engine in the C5 has been discussed a few times in the A6 forums.

In a nut shell, the best two options would be to a) get an RS6, which will then come with the whole package, b) get the engine supercharged, c) spend lots of time and money to try and create a turbocharged S6. I haven't read of anyone doing so yet.

As for the 2.7T, if you can get a manual, that may work out cheaper (not sure by how much), and it looks like you have done quite a bit of work with turbos already. Only downside is that you don't get the 4.2 wide body.

From memory, so the numbers might be a little off, RS4 was 380hp, S6 340hp, RS6 440hp, supercharged S6 around 450hp, but the auto transmission will also need some work in the long run. The S6, RS6 weren't available in the US in manual.

I hope I've helped rather than created more question...

Good luck whichever route you go.

 

katcoota, very helpful in deed.

Logically, getting an RS6 would be best; but not many around and pricey.
Nice combo would be the S6 body and the 2.7T

"RS4 was 380hp, S6 340hp, RS6 440hp": the 2.7T will make 460 HP and 455 lb*ft

"S6, RS6 weren't available in the US in manual": what is the model/designation of the A6, S6 and RS6 auto trans? At least the S6 and RS6 trans should handle the 2.7T power.

Maybe I am overcritical to the 4.2, but in the past, it left with a very 'front heavy' impression (understeer) and overall 'heft' (heavy handling); which is why I like how the A4 1.8T drives.


Scenario 1: A6 2.7, manual; turbo upgrade, suspension work
Scenario 2: A6 2.7, auto: turbo upgrade, suspension work, auto trans upgrade
Scenario 3: A6 4.2, auto; hope to find parts to add turbo, or simple supercharger

I am going to explore 1 and 2 now.

 

I used to drive a 98 a4 2.8 and I had the same feelings. I wanted something bigger, faster, and nimbler. I bought the 2.7 a6 and counldn't be happier. Its was faster than my a4 was (though the difference would be smaller with your a4) and it has all the room I need. IMHO I prefer the handling of the heavier a6. I didn't like how responsive the a4 was to every single thing in the road. The extra weight smooths things out especially once you beef up the suspension. I suppose you could equate it to driving a crotch rocket vs a harley. I'm more of a cruiser kind of guy

 

get an A6 with a manual and a 2.7t and go bigger turbos.. RS6's or tial 605's.. 600 bhp.. not too shabby...