Well I've tinkerd with my '99 wr400 for about the last 3 yrs (as long as I've had it) and feel like I've got as much power out of her without dropping alot of cash. It runs great, but I've recently riddin a 2006 crf450x and realized just how far the technology has come. Rather than dropping alot of cash into an outdated bike I'm ready to upgrade. It was a big learning curve working on the thumper after growing up on the 2 bangers and I guess one of my concerns is how much different is working on the newer 4 strokes? Are the newer FCR carbs drastically different and is it very difficult to get to them with the new alum. frames? How trust worthy have the e-starts proven to be? With regular maintainence the 400 has been pretty bullet proof. Can the same be said for the newer generations? What other mechanical issue will I have to watch out for? I appreciate your input.