my 250x is a '87 model. it currently has the stock suspension front and back. i have been looking on ebay and all of the 300ex, 400ex, and 450r a-arms seem to cost about the same. which ones would be the best to go with? and what all do i need to complete the change? i trail ride and really dont do any jumping. i just want something that will handle and ride really well. the ole back can't handle it like it use to. any thought much appreciated.