So I have a 99 discovery with original suspension (I know I should have changed it already), and I just had to get a bigger trailer to pull the my kids Motocross bikes and gear to the races, and got an 8x16 trailer, and need to beef up the rear and probably the front shocks. what do you guys reccomend - i'm pulling about 4000 lbs......

 

Bilstein, OME and TerraFirma all make quality replacement shocks.

 

First, as old as your suspension is, if you want to get it back into shape, you must replace both the coils and shocks, both front and rear. Shocks by them selves will not help you with warn coils when you are wanting to pull a 4000 pound trailer.