Although I enjoyed the overall experience, after two days in the standard Audi S5, the S in the name sort of hit me like the bogus R/T badge on a flurry of recent crap-ass Dodges. Far from crap-ass in this case, but still suffering from a lack of cojones. So I called MTM, German Audi tuners extraordinaire, to see what was cooking for the S5. The reply was: the MTM GT S5 Supercharged.
MTM knows that stock Audi Quattros are heavy and need less weight, more grunt, or (preferably) both. Some fundamental chassis touches can also go a long way in corralling the moving mass through and out of curves.
And grunt there is, with the dial turned up to 492 hp at 6800 rpm from the standard 354, courtesy of the engine bay-dominating Opcon supercharger from Sweden pushing 8.7 psi of boost into the 4.2-liter V8. All-important torque also rises to 398 lb-ft peaking at 3800 rpm versus the stock S5's 325 lb-ft, which sweet-spots at 3500. Although weight remains relatively close to the S5's quoted unladen heft of 3,891 pounds, all that ready power and torque brings the 60-mph dash time down from 4.9 seconds to a more serious 4.4 ticks.
Given space limitations under the hood, MTM and Opcon had to essentially create a custom compressor (even though the basic unit is the same one found on MTM's B7 RS4 Club Sport) because the air intake had to be drilled into the side of the engine-top blower. With the breathing assistance bolted on, the compression ratio drops from the S5's 11:1 to a more accommodating 9:1.
Forward thrust notwithstanding, this is the finest-dancing B8-based car I've encountered. The relatively civilian Audi dampers remain in place, but MTM has banged heads with partner H&R to come up with a really nice set of 685 pound/inch springs that widen the performance range of the standard Ingolstadt legs. Besides these more robust bouncers, the well-filling 10.5x21 forged MTM Bimoto nine-spoke wheels and medium-rigid (96Y) 295/35 Michelin Pilot Sport PS2s help the GT S5 devour the pavement with authority. The steering becomes heavy, but also incredibly precise for a fat Quattro. Enhancing this tendency even more are the 10mm spacers and 40mm offset at all corners.
The 13-inch rear brake discs with single-piston floating calipers in back are straight from the S5 production line, but the front shoes get switched out to a spiffy set of eight-piston fixed Brembo calipers, with 15-inch discs supplied by Performance Friction in the USA. These sport a special dimpling technique that stops short of full-on perforation to avoid cracking.