I've had both the Poison Spyder/Solid diff covers. Both are great, can't beat the Solid covers for the price!

 

I've got PSC on the front and rear. My buddy has riddler, another has SOLID, and a couple guys in my club run blue torch covers (DIY). I haven't trail tested mine yet, but have seen them in use. Everyone beats the crap out of their covers and haven't seen anything to complain about. SOLID is a fantastic deal for the price.

Or take two stock 30 covers and weld them together haha