whether a stabilizer is "crappy" or not depends on what track u use it on. Each stabilizer (blue, red, yellow normally for tamiya) is a different thickness, used for different types of surfaces and tracks.
Depending on your racing level, those bubbles can mean nothing or everything. Normally, i move the piston up and down a few times to get the bubbles to come out... then i let the pistons just sit for an hr... before putting the plastic seal on.
Since i am just a parking lot racer at best, small amount of bubbles don't mean anything to me. If you want to get anal, you can place your pistons in a vacuum pump and suck all the bubbles out from them, but i think that is unnecessary for lower levels of racing. Better focus on driving than spending cash to perfect the details.