Anyone had any experience with aftermarket tactical handguards for the AR platform? I have an AR-15A2 with 20" barrel and standard handguards and I want to get a set of tactical handguards so I can mount a bi-pod and maybe a surefire or similar light with a remote swtich. My cousin is a Indiana State Trooper and he has 3 AR's and he told me it's kinda a hit-or-miss situation with those aftermarket handguards. He said sometimes they fit and sometimes they won't. I'm looking for a good high qual. set that is relatively cheap.