Race Upgrades For Matrix TR "FRE"

[Takedown]

Well I figure that Ill have around $250 at the end of next week sometime and I am about to make a list for my Cen Matrix TR Arena FRE truggy. Ive decided that Im gonna put the purchase of buying a neu motor on hold yet again. Remember this setup is for racing. Heres what I had in mind.

ESC- Modded MM "Already installed" Possibly a MMM
Motor- Align 600xl "Positive this is what I want"
Lipo- Flightpower 3200mah 5s 30-60c "Will be getting 5s 5000mah TP or FP soon"
Cap Board- (8) 330uf 50v caps. "For cooling"
BEC- CC BEC
Servo- Hitec 5645mg Digital Ultra Torque "Already installed"
Radio- Futaba 3pm FM "Already have"


I would like to know what other upgrades would you reccomend for this? I plan to run long 10-15min mains. What gearing would be optimal? Thanks