In no order 
  
Bodywork tidy up 
re bush 90% of the suspension 
baffle sump 
try and come up with a hydro system that idea is dual caliper and keeps the cable brake 
Decent exhaust system 
more adjustable arms with a GOOD geo 
Roll cage 
Aftermarket Diff 
New wheels if there enough budget but then i bet only 50% this actually gets done for next season  
  
  
Edit; more arch liners