I don't know much about the is300, but I'm sure there are others that do. I would try some Toyota forums and do some searching.

I would hold off dumping $$$ into it until you improve your driving. Personally I would get some decent street tires and maybe do some auto-x events and build up you car control skills.

Then keep an eye out for drift events that offer on track instruction/seat time. I know they will have one at NASA Hyperfest.

Then, as you get better improve your car as needed.