In either 2005 or 2004 they added reverse to the 400ex.
The 400ex’s are very reliable with 440 kits. I’ve built two of them for mx and they outlasted the quads, depends on the piston thats all.
I’m selling a 2006 ltr450 with extras if your interested though, yosh pipe, cherry bomb, renthals, handguards, pro-armor bumper, grab bar, skidplate and suzuki nerf bars. also has all around beadlocks with newer maxxis razr mx’s.