It's good enough stock - you will perhaps get slightly better range and accuracy out of it by swapping to a maple leaf autobot bucking or similar - but this isn't essential. If you want to definitely tighten things up, then an aftermarket hop of the likes of the Action Army CNC hop will likely improve things a little more. But because these guns are so good out of the box, the differences aren't going to be spectacular. For a holster, i use the Swiss Arms Adaptex universal holster - its a solid polymer trigger retention holster than can be adjusted to fit different pistols. They seem hard to find these days, but there are other universal polymer holsters on the market. Much better than the soft fabric ones that leave the mag catch vulnerable and lead to endless lost mags..... I'm not sure I'd bother with a silencer personally, being a blowback, its not going to make much noise difference (unlike on your Mk23s)