Is there a diffrent way to repair/ modify the rear shocks on a 4wd madza mpv from the factory self adjusting load leveling shocks to a more economical(cheeper) Less expensive brand or type of shock?

the current dealer price is $400 A SHOCK which realy is a shock.

Can we just replace the whole thing with regular load lvling air shocks? is there a Rebuild kit for the Old shocks? please help..