Ok, so I am in the process of buying an Audi. I am in love with the b5 s4. But, I have heard more than once that the s4 can be a little less reliable than the a4 (say... b5 1.8t). One of my goals with buying this car (either a4 or s4) is that i want to be able to keep up, if not beat an '06 mustang gt ( wouldn't mind putting some sti drivers in their place either). Is the 1.8t capable? or another a4 perhaps? or would i be best off with the s4? Are the negatives (if any?) that come with the s4 worth it? I would be buying it used, so how many miles on the car is too many? Any inquiries please. thanks

I dont know much about the s4's except the 2.7T is the same as the A6 2.7T, smaller body though and considerably lighter. The s4 can really be turned up. The boost is set at I think 8psi with a lot of room to spare. 230hp I should think.

I own a 2.8 12 valve A4 and if its reliability youre looking for, this is it. The 1.8T is the least reliable and then the 30valve 2.8. You cant do much with the 2.8 12 valve though except for CAI and exhaust which even then wont give you considerable gains. It has 172 hp.

The 2.8 30-valve has 190 hp and you can add a supercharger to it.

Thats my $0.02. Happy Hunting!

get the 2.7t. i believe it is the same engine only de-tuned that is in the original RS4 and that car is amazing. believe me. i ran into a debaged version in DC. its lighter than the v8s currently in the s's, and has way more power potential. try to find one with less than 100000 miles on it bc it seems that audi had some reliablility issues in its earlier models. also beware of the clutch. it is mated to the stock numbers the engine produces. if you want more power out of the 2.7 get a new clutch, bc the stock one wont last long. audi's are heavy so you want to go with the lighter models if you want to teach an sti a thing or two. the twin screw v6 is definatly the way to go though. as for the 06 mustang... they are slow. a remapped 2.0t will take it down. just some food for thought.

^+1 this guy know what he is talking about