Just bought another zilla a 89 this time wish I still had my old 90 what engine mods do you guys think I should do and have the best bang for the buck, Looking at a Q 2.0 pipe and silencer Q head mod and o ringed V force 3 reed cages and 41.5 or 42.5 bore the carb leaning more to the 41.5 carb any ideas, options, opinions would be greatly appreciated. Plan on running 110 vp race fuel so compression is not a issue. looking to make good mid to upper rpm horsepower, mainly a dune rider and some woods trails. any input would be appreciated. 

Send your head to Hall's have it cut for O-rings and the chamber re-cut to give about 14/1 compression, run that good gas, find a LRD lowboy pipe, (hard to find) ......LEAVE THE REST ALONE.  Gear it up a bit,  It will be a torque monster and a blast to ride.