Money Well Spent
If you're looking to spend good money on a modified IS convertible, look no further than the $2,346 wheel/tire upgrade and add it to the $1,588 for springs, shocks and antiroll bars. The resulting $3,934 is a reasonable amount to spend on the 2010 Lexus IS 350C's chassis, and here's why.

The forged-aluminum wheels reduce unsprung weight by 21 pounds (5.5 pounds at each 19-by-8-inch front wheel; 5 pounds at each 19-by-9-inch rear wheel), plus they look undeniably cool. Combined with supple Bilstein dampers, the new springs reduce ride height by 1.3 inches in the front and 0.9 inch in the rear. The antiroll bars are 105 percent stiffer up front and 320 percent stiffer in the rear. What does this all mean? It means the lower chassis is more responsive, the handling balance is a little livelier and the tauter suspension calibration works the new Michelin Sport PS2 tires harder.

As is usually the case with such suspension kits — especially when they're applied to convertibles — we were guardedly optimistic (a.k.a. "suspicious") about this one's ability to deliver a car that works well both at the track and in the real world. But the F-Sport hardware comes through.

With a slalom speed of 68.2 mph and an average lateral acceleration of 0.89g around the skid pad, the 2010 Lexus IS 350C F-Sport has improved by 1.4 mph and 0.02g respectively over the much lighter IS 350 sedan. Moreover, there's only a negligible decline in ride quality and almost no increase in road noise. What's more, the convertible's sturdy structure doesn't mind the added firmness and remains taut and rattle-free. Better grip, more control, better stance and virtually the same ride qualities. Sign us up.