So, yes you should replace your wheel hub adapters in metal some people even take it as far as cutting the rear rim to clear a bigger stud into the wheel hex. On top of that i would recommend the same thing I was told to change going from brushed to brush-less. The shocks front is for weight displacement and better handling of weight and power. Rear shocks of course to support the added weight. not the rear shock tower leave it plastic ( if changed to metal you risk breaking parts due to momentum distribution) the front shock tower can go metal if you want for weight dist. otherwise for show. the front A arms wheel hub and steering hub should go metal for weight dist. durability for increased power. I am currently finding a lot of problems sourcing reliable linkage to go to metal adjustable's to get better tracking in straights. now that weight is out of the way you need to control the increased power do not go straight for tires! first switch out your transmission gears for metal and use a lube compound for gears and bushings. some people would say you need increased bushings this is not totally accurate. all you need is a good built bearing from a good source. Next source a good set of pinion gears to try out different mesh settings foremost then find which one for your gear setting ( acc. or top speed) next will be updating your spur gear to metal also adjust your spur gear spring accordingly for the different gear setup but also so you have proper slippage when needed. i have found that the HR Star Drive steel axles SECT288X06 fit with no modifications and i have yet to have one break. I do a lot of skate park bashing just to compare the level of abuse on these trucks. I have also gone with the HR aluminum steering saver ECT4806 and the HR 87 T spur gear SECT887. I have yet to have any issues with these parts directly so far.