Welcome from a fellow Newbie, I just bought a 2010 IS250 C on Monday, 16k miles from a local Chevy dealer who took it on trade on Surban!
Traded it in on 325Cic with 60k, that I knew was going to be expensive in the coming months. Mine is the 'basic' Lex (oxymoron?), no Nav which I don't care about-got a TomTom, but would have liked the memory seats.
Thrilled with the Lex, just knocking around town we are getting 26mpg according to the computer, won't know until I do my first fill for real. BMW got 19mpg in same conditions.
Too hot here (Cave Creek AZ) to have top down, around 100 since we bought it.
Couple of things I really like the BlueTooth for phone and streaming audio from my iPhone. I've had it on other cars, but never worked well this works great. Softer ride than the BMW, much quieter with the 'hardtop'. Cooled seats, another great feature. Plus, just watching the roof go up and down, what a miracle of engineering!
Only negative I've picked up from reading the forum is water pumps can go out from 30k on. Some have over 100k with no problems but several around the 50-60k mark.
Two suggestions, if you haven't done it, read the big fat ops manual, a load of information in there, some of which you'd only find by chance. 2nd, be careful opening roof in any garage, trunk lid comes up quite a way.
BTW, what tires are you going with if you replace them?
Enjoy, we are!