It's according to what you plan to use it for. If you're going to use it as a carry gun I would leave the stock connector in it. If you're using it for plinking/target shooting go ahead with the 3.5# connector. Either way I would polish the internals. The polishing makes it much smoother. I keep anything I carry stock. The Glocks I use for target and hunting have the 3.5# connector, polished internals, heavier trigger spring, pre-travel and overtravel adjustments. Just my opinion.