hephey
First of all, let me say that I am no PRO driver, so some people might have a different opinion than me, but I would like to help you.
1# spare parts: Wishbone, Front: U3407.
Wishbone, rear: U4184
Suspension Block Set :U4182
these parts breakage always first, and those you just have 1-2 sets of each.
And I recommend that you use RW Spur Gear: RW48K198.
2# upgrades: 1# Gear diff; Front and rear: sorry cant remenber part nr.
do not throw your ball diff away, they can still be used on some tracks as part of your setup
2# CORE RC Big Bore Spring Med : CR177
3# CORE RC Big Bore Spring Long : CR178
4# Roll Bar Set Rear: U4172
5# Roll Bar Set Front: U4165
6# Alloy Yoke; 7.5deg: U3404
7# Schumacher Alloy M3x6 Spacer :U2858
8# Pivot Block Front 10 degree :U3556 U need a rear part to.
9# Rear Alloy Block Conversion Set : U4160 (Nice to have)
10# FAB Front Adjustable Brake : U4133 NEED Part!
There are many more parts you can use but this is the part I always end up using and the ones I use most.
I hope this can help you
HEPHEY from Denmark