I personnaly have owned and fielded a TM G36C for almost 1.5 years. I changed the front end for the bigger one and work with 9.6v 3000mah batteries. Before I changed more parts all I had was Systema metal bhushings and a Systema M100 spring. The ROF was more than OK and it was reliable. Since then I changed the inner barrel for a M4 lenght Systema 6.04 (with a silencer) and changed the spring (prometheus), spring guide (prometheus), a Systema silent head set and everything else is stock. Keep in mind that the stock gears of a V.3 gearbox are very sturdy. However if you want more ROF than you have to change them and the motor like previously mentionned. I would go in steps so you can judge as you go. That could avoid spending too much cash for maybe nothing...
My 2 cents!!
