I really don't count a fuel filter and air filter, and return spring as hop ups, rather a necessity, all three can be had for under $20. Once these are done, then I would suggest shocks, fail safe and a steering servo, the failsafe for obvious reasons, the shocks because the stock ones pretty much suck, same reason for the steering servo. Once you replace the steering servo, move the stock one to the throttle/break position. Then replace parts as you break them with better parts.