Kawaguy:
I have a 2005 CR500AF. They can be jumped as high as you desire and they are several pounds lighter than a 450f and even 2 pounds lighter than a 250F. The 2005 AF is the CRF250 chasis but the 500 2-Stroke motor weighs 2 pounds less.
The bike handles great, I just rode mine this past Saturday back to back with a friends 2005 CRF450. The 450 is way tame in comparison, that's a good thing to me. If you ride the 500 in third for most MX corners the power is way smooth and plentyful. My friend is an average 250 Int. rider. He and an other friend were in a heated battle in practice this Saturday coming into a long sweeper that leads to a long uphill section. I set up outside of them coming into the sweeper and twisted the throttle the the stop, the rear end drifted out and I cut under both of them and was gone. The power if very managable and the bike is actually smaller than the 450 and corners much better.
I'm 40 years young and the track I race at has a 45 foot double after a tight tunnel turn and a 80 foot triple after a crapy step down and I do them with out any concern. Before on my YZ250 I would have to set up just right or forget it. On the 500 you can just get thru the corner and roll on the throttle and have plenty of power for anything that other bikes are pinned for.
I'm just now getting comfortable with the new chassis, I have been on Yammaha's for the past five years. The 2005 AF feels great and when ordered set up with their suspention offerings handles great too. I can turn the CR500AF inside of the CRF450 all day long.
As far as cost goes, their web site has a break down. I have around 12 K in my bike but I have the base bike plus front and rear suspension upgrades including the Enzo sub tanks, Eric Gore ported cylinder, Tag Matrix clamps and fat bars, factory connection pro perch, skid plate, spare wheel sets, DID gold chain, 49 tooth rear sprocket, Pro Curcuit wide pegs, aluminum throttle tube, Twin Air filter, Factory Connection radiator braces.
The sky is the limit but when you get it you will have the best bike on the track. All the stuff I mentioned isn't neccesary but it's what I wanted for my bike. You will pay $8,999.00 plus $350.00 shipping for the base bike.
Good luck,
Mark