Grew up riding 4-strokes and looking to get back into it with my son. I don't pretend to be race material but I do generally ride a bike hard. The bike will be used primarily for trails but will include jumps, hills and the occasional track visit. I'm 5'-11", 175 lbs and train (triathlons) every day. The bikes I'm considering include the 07-09 CRF 250R, CRF 250X, CRF 450X or even one of the KTM (XC 250F or similar) models. It's the same old story - don't need too much bike (is the 450 too much) but also don't want to be disappointed with the power/suspension of too little bike (250X ?). Experienced suggestions are appreciated.