Ok my slayer is all upgraded but i like to work on it and i want to put more stuff in it ! ..

I Got sway bar
Spring front and rear 50wt oil in shock
Proline tire
Proline rims
New air filter
new servo
new 3.3 engin ... What else ...

I dont have any Aluminium parts on it ...

Sould i put the rear brake? is it valuable? And how is it to install that ?
Or i sould keep money to buy another basher or some expensive nitro gas?