Personally i would check the car over make sure its in good running order then take it to the track before buying spare wheels and brakes or changing the suspension.
Obviosuly if you have the spare cash to do that then go for it.
I used to track my saxo standard before seeing what i needed/wanted and the same with the EK9 i tracked that with **** budget tyres and oem pads before moving onto different tyres and pads.
A standard car can still be fun, it's only when you start finding the limits of the car you need to look at upgrading / changing parts.
A decent driver in a standard car will be quicker/safer round a track than someone whos spent money on their car but has no idea how to drive.
Just remember it's not a race and don't go balls deep first off.
Supersonic blue
Edit: picture adde above
good to see people being supportive. my brother used to use ej9's on track all the time, ok they had done a lot of work getting the suspention and geo sorted, also heaverly braced with bigger brakes and stripped but they had a right good time. i think you could be suprised by your car