The TC3 is a VERY good car. You'll love it. I still love mine and I own three
No need to buy TC4 parts. MOST hobby shops still carry parts. Also check out Towerhobbies.com. They still have every part, hopups, nut/bolts for the car. You could buy anything and everything you need for cheap price on tower.
Also peep out and find a TC3 thread lots of good info about them on setups for racing or bashing.
For best info on them check out the forum at RC car action.