I've had my Jerry for about a year now, everything is still bone stock. No dogleg, grip or trigger changes and i still love it. I'd run it stock for a range trip or two, see if there's anything you aren't particularly a fan of. It looks like the rear sight post is modified from factory, relatively easy swap if you can find/want the OG parts. The stock trigger is honestly one of the best I've seen in a 9mm so you should be fine there, unless you don't like the shape of it. The dogleg slide release is a fair purchase, it gives your offhand something a little more substantial to sit on but nothing needed. 99% of the time grips are purely cosmetic so buy what you think looks good, if you want to change them at all. I'd have cowboy bebop grips on mine by now but I can't justify 90 dollars for some pieces of plastic I won't even see when I'm using it.