Hmm. I say A4. If you like to tinker yourself, you will actually be disappointed with the S4. You can't do anything to it without pulling the engine out. Plenty of knowledgeable people actually say the A4 is more fun through the twisties due to better weight distribution and (much) lower overall weight. The A4 is definitely more moddable, and more fun to mod if you work on your own car.
The S4 is obviously faster, and has higher brute power potential, but a manual A4 1.8t is the serious Audi-loving modder's choice.

Besides, for the difference between the A4 and the S4 you're looking at, you could buy a big-*** turbo/fueling, clutch, FMIC, suspension and wheels, if you put it all on yourself.

There's a guy on AW right now who wants to trade his modded S4 for a 1.8T.
http://forums.audiworld.com/a4/msgs/2418777.phtml

 

Let us pause for a moment and ponder the situation at hand..... hummmm......

S4: $12,500

A4: $4,500


Difference: $8,000

Options:

Buy the S4.... pay more in taxes and not have any money to put into it.....

Buy the A4...... have the diff of $8,000 to put into it and STOMP on any S4 and make him go home and cry.

I don't even see the problem.

 

^^^^YESSS. And modding S4s can be more problematic, i.e. turbo failure, as well as super more expensive.

 

just make sure its quattro front wheel drive sucks so much its not even funny

 

Well, yeah. There's absolutely no reason to buy an A4 for performance mods unless you get a Quattro. Otherwise, you'd just be buying a tiny-displacement, fat-*** sedan. For the price of a Frontrak A4 you could just get a DSM non-AWD and buy a big turbo.

 

Awww DSM you want problems buy a talon haha o man everything breaks on those

 

S4, sounds like a great deal. but the A4 i cheap also. personally id go with the S4. i love them, love hearing the turboS spool up, love the exterior look, wheels, gauges. etc. But if u dont care for thoughs things, then go with the A4. either way, ur goin to have a badass audi