New Supra...lots of little problems.

[suprra_girl]

does it feel like the rear of the car that jolts or the steering part or what?

if you car is overheating forget mods for now

you need to figure out why it's overheating... is your cooling system full?
do you hear gurgling in the dashboard on cold start
when does it overheat... traffic/high speed/high rpm?
replace your thermostat (they're cheap)
don't forget to burp the car when you replace the thermostat

have you done a compression check
block test
(local mechanic can do this or you can buy the kit)