Would I have a problem with cheap pistons with a Colt. I always try to buy the best.
Most Colts are DI gas (direct impingement, eg old school/standard gas systems) not pistons. I haven't seen a Colt piston gun yet. (They may or may not exist, don't know if Colt bothered to roll one out yet). Guns like the 6920, 6940, etc, are DI gas guns. I wouldn't even buy a piston gun on an AR platform but that's just me. DI is fine and it saves you a little weight and complexity, and it keeps the parts standard.
-Mike