Hey guys! So I have a yz250 (96) and a kx100 (00) for my lady. I wont be racing these bikes. Just trails and desert. Her bike already has a desert tank. What else do I need to make these bikes run reliably on trails? I want to get these rims. Is 18 in better than 19 for trails? Will they still fit even though its for the 99 model and not 96? Also what are some good tires to mount on them? http://www.rockymountainatvmc.com/p/1071/-/938642/Tusk-Impact-Complete-Front-Rear-Wheel-Kit-1.60-x-21-2.15-x-18-Black-Rim-Silver-Spoke-Blue-Hub?v=1618 Is a flywheel weight needed? why?