I put 70 series tire on (same as an older VW bug). That set off all the electronic warnings. The ABS sensor light came on, the traction control software (yellow triangle) came on along with the engine check light. If that wasn't bad enough the software took over and the car would not go more than 5 miles per hour. I already drive the car like a 120 year old lady. I don't go over 65 miles per hour. Accelerate out sooooooooo slow. I coast up to lights and coast down hills. The real problem is the 4:52 rear gear. The car is doing 3,500rpm on the freeway when other cars next to you with overdrive will run as low as 1,800rpm. This engine will only have a "half life". I runs like a weedwacker on the freeway and will never make it to 150,000 miles. My last Toyota and Mazda made it to 300,000 but this car will not at this rate. If the people at smart are reading these posts PLEASE give us a 6 speed trans and a clutch. Get rid of half the electronics on the car and go back to SIMPLE.