I'll more or less second what Pedro is saying, while I think its great that you want to upgrade your tires, which is the single best upgrade, but if you want to upgrade them, wait until you've done it a few tires and go from there and save the money for the best that particular class allows. At first you are going to mess up a lot.. and when you go too hot into a color and jam on the brakes, try to turn, and push through the corner, you're going to cook off a ton of tire. Now that can be extremely cheap multimiles that you will learn more about proper driving, weight transfer, what the car does at the limit (as you'll be over the limit a lot with those), etc etc, thus making you a better driver. Or, it can be expensive in the middle of the road tires that you wont be learning as much from and may never be able to realize your full potential. (plus learning with the cheap tires to go slow to go fast will be much easier...)
But, as always the choice is yours. Even if you decide you want to upgrade soon, at least try an event or two (storyland yay!) on the crap ones and there wont be as much pressure to upgrade ASAP. (just a thought).
FYI: Unofficially I think only 7 weekends to prepare for the tenetive Storyland dates April 28th and 29th.
