actually, if it were me, I'd run 235/45/17 tires. If you are worried about speedo reading errer, dont; as machenical speedo's are not very accuate to begin with, second is the maximum load carring avalible for the given tires. 225/50/16 (stock) tires average between 1350 and 1400lbs both 225/45/17 and 235/40/17 average between 1250 and 1300lbs. where as 235/45/17 tend to average between 1375 and 1425lbs.
Once you exceed the maximum load capacity you exceed the the tires maximum traction avaliblity. Having just seen the thread about about the corner weight of a fellow members supra, the drivers front was 1017lbs. so using his car as an example, lets say that you were making a right hand turn at a moderate rate of speed and you had to brake, while doing so it would be fairly easy to achive a 3 to 400lb. dynamic weight transfer in this situation and would therefor load the drivers front tire that additional 3 to 400lbs. causing a vertical load of 1300 to 1400lbs.
This is the reason why corner weighting and control of dynamic weight transfer is so important on a race car as it allows the tires to do there job and not over work them.
