I have an A3, and a few people have asked, as I obviously enjoy making it go very fast round in circles, why Im not running an S3. So I thought Id post here, and it should hopefully give some people an idea of exactly how good the A3 series can be for the money in comparison to an S3. Lets compare completely standard cars, buy them, upgrade them and look at the respective output. So, a slightly upgraded S3 would consist of: S3, lets say we go for a pre facelift to save money, but FASH and in good order = 8.5K Dampers and Springs, Bilsteins or H&Rs = £650 Tie Bars to account for the lowering with the above = £250 H&R Anti Roll Bars to again, go with the above = £300 Remap, lets say Custom Code (260ish Bhp and 280ish ft.lbs) = £450 Forge TIP = £130 Forge DV007p Recirculating valve = £80 Black Diamond grooved discs front and rear = £200 Ferodo DS2500 front pads = £130 Standard Fast Road rear pads = £50 DOT 5.1 Brake fluid change = £30 Oil and filter change, using proper spec parts = £50 Milltek Cat back (the S3 Cat isnt restrictive) = £300 So total price for a reasonably upgraded, well handling, fast S3 would be £11,120 This obviously assumes you are doing all the work yourself, which isnt impossible, about the only thing I would prefer a garage to do would be to fit the exhaust, as a ramp is ideally needed. Ok, now onto the A3: Decent mileage A3, Id try and get an AGU as less issues with large power upgrades should you so choose in the future = £5K Dampers and springs/Adjustable Coilovers = £550 Eibach Anti Roll Bars = £250 Remap, Custom Code again (For K03s on AGU, 235Bhp and 250ft.lbs) = £350 Forge TIP = £130 K03s from eBay = £170 Forge 007p DV = £80 FMIC for AGU = £300 312mm Caliper carriers = £120 Black Diamond discs and pads = £200 Ferodo DS2500 front pads = £130 Standard Fast Road rear pads = £50 DOT 5.1 Brake fluid change = £30 Oil and filter change, using proper spec parts = £50 Milltek Cat back (the S3 Cat isnt restrictive) = £300 Peloquin Limited Slip Diff to take care of power distribution = £700 So total price for the A3 = £8410 So, using the above details, you can see why the A3 is a very, VERY good option, a fully specced A3 is less money than a standard S3!!!! With the K03s you are getting essentially K04 internals with a K03 housing so it can handle higher pressure and thus can be very nicely remapped. The power curve is preferable compared to your Revo type K04 remap also below 5k rpm. Also within the A3 price I have included an AGU Front mount intercooler (the £300 one from eBay with the massive thread on VWVortex), which is much more efficient than the twin S3 setup, thus allowing you to hold the boost for longer on your K03s than a remapped K04 on an S3. The haldex advantage is more or less totally lost also, as a Peloquin LSD in the A3 makes a very good car for putting the power down properly and of course you save 300Kgs weight by losing the Quattro system. Once you upgrade the A3 to 312mm and use decent discs and pads, the braking is exactly the same, the rears do very little work so the vented 256mm on the S3 compared to the solid 239mm on the A3s isnt an issue. So to sum up, for the price of a standard secondhand S3, you can build an A3 which has rough figures of 204Bhp per tonne. The remapped and 2.5K more expensive S3 would have 185Bhp per tonne. We know that pure numbers based BHP doesnt really matter until you are pushing 80mph, so the 30Bhp extra on the S3 matters on straights only, all other track work is below/around this speed. As is 99% of road driving, so its a small consideration. We can also see that the A3 is 300kgs lighter (3 peoples weight) So in essence, using the A3 as a base for a fast car saves you 2.5k at least, produces a faster overall car that can maintain boost for longer and upgrade potential to big turbos is also better due to the AGU internals. Any thoughts on that?