If you just want a bit more performance cheaply then lighter rollers, stiffer torque spring, stiffer clutch fly springs,, race variator, sports exhaust, open air filter, etc, etc. You will never get ferrari performance from a hatchback tho so dont expect miracles, you should get a reasonable improvement tho if you can balance the tuning nice.
For paint you can rattlecan it and get good results if you do the prep and paint right. Prep is the key, prep takes all the time to do, painting wont even take 1/10 of the time. Use an abrasive pad or fine sandpaper over all the plastic parts, make sjre you get all the edges and bends properly. You want to end up with all the existing paint looking dull after sanding, you dont need to sand it all off. Then use plastic primer on it, 2-3 thin coats. Next spray on the top colour, i usually do 4-5 thin coats, followed by 3-5 coats of laquer. Leave it all for at least a week-2wks to fully harden before rebuilding it, or if you cant wait then give it a day or 2 and just be extra careful with the soft paint, it will scratch easily. After 2-3 weeks it should be fully hard and then just treat it as normal and wax and wash as before.
If your not happy painting yourself you can still remove the panels and sand them then get a paint shop to spray them, be cheaoer that way since youre doing the dismantling and some of the prep.
