If you don't want to spend the 100 bucks or so that is costs to buy a pdi hop up, I'd say get a metal hop up arm for your L96, it may not have the same air seal and all, but it does replace the crappy plastic arm that bends after a while or snaps from accidental over tightening.
http://www.landwarriorairsoft.com/acatalog/ASPUK-L96-Metal-Hop-Lever-ASPUK_L96_MHL.html#.UFgDLlIRR8F
This is probably the cheapest alternative to upgrading your hop up without having to spend $100