Basically looking to stock up on the bits that either wear or are likely to get damaged..
e.g. front arms (wide whites), caster blocks, idle gears (can't get enough of those...
), suspension mounts, hub carriers, dogbones, diff balls, diff rings, etc etc etc.
Also really looking out for an original brace-style battery strap to hold non-stick packs in...
Luckily lots of parts are still available new, but usually only in black and the lead-time for parts to come in from the USA can be annoying and sometimes expensive (esp if you're unlucky enough for hm customs to decide to get involved)!
Cheers,
Ty