The IS300 isn't that fast really, the best stock 1/4 times I've ever heard of is 14.9 seconds, and 0-60 is maybe 7.2...about equal with my friend's SVT Focus. Of course they are very mod-able, people get them up over 400 rear-wheel horsepower all the time with just a Stage 2 turbo. But I don't have the money for big mods.
So wait, the EX doesn't necessarily come with leather? I get the impression from all the classifieds I see, that pretty much every EX that Honda makes comes packaged with leather.