Just for a little perspective: Look at the new GTO, similal weight distribution as a B-body. IRS and Motor Trend shows 8.0G on the skidpad, 63.5 in the slalom. 94 Impala SS had similar numbers. Solid rear axle Camaro SS pulled harder on the skidpad with inferior Goodyear F1's. All are about 55/45 weight distribution. Not that MT is any kind of authoritive source but it is comparing cars with similar procedures from 94 to 04. Or consider similar tests of Jaguars $80,000+ Vanden Plas and XKR; 59mph for the VP,63 mph for the XKR, in the slalom. Both with IRS. Certainly true that these numbers are not the whole story of how a car handles. Or a 03 Cobra with IRS at 65 mph slalom VS a 01 Bullitt with solid rear axle at 63.5 mph slalom. Lots of variables in even these few examples but it should illuminate the point that IRS is not some panacea. FWIW I've seen and driven a privately owned tubular frame, center drive truck arm car at the Silver State Classic. Fabulous transient handling, documented at over 1.1G lateral acceleration,very street livable car, all with a solid rear axle.