I'm not sure about after market seals but I think they are oem.

as for the shocks. You don't buy listed shocks for the truck thats modded. You measure the full length extension and compresion, now this will give you the shock length.
Now you just need to pick which compression rate and rebound. This is dependent on your vech weight and spring rate. Ie for the mitsu'd if they are cranked the compresion should about med. Etc.. shocks are not rocket science. Unless your setting up for the baja or jumping it's easy.

sorry about the shock stuff. I'm getting something for this lift. (cheap)But with this system of choosing. Well the baja racing guys at the shop are getting them.