Yep, the 602s like power and the hog tunes setup is an entry level low budget system. Nothing wrong with that, but it is what it is. It all comes down to how much you want to spend and what you want to do in the future. If you know for sure you're sticking to a 2 speaker setup and want to keep the cost down the 602s are a very good coax and since you already have them might as well build around them. Try to find a used biketronics 2180 (4180 if you want rear speakers later) or arc audio 600.4 amp and you're in great shape for a few hundred bucks. Will need a BT line leveler to flatten the signal from the HU. The diamond audio micro 4V2 is a very nice amp bridged as well and you may be able to find one of those cheap used. It fits in the RG between the radio bracket and headlamp bracket like it was designed to go there.
Check the classifieds here and the other big forum, will be pretty easy to find over the next couple of months with guys changing their setups over winter. No need to mess with the stock harness at all, plenty of outfits make the fittings that tie right to the existing system without cutting a single wire. If you want to go big that's a whole different discussion, let everyone know your budget and goals and others will chime in.
Freedom isn't free, remember to thank a vet.
2018 CVO RG lava orange, 117 Stage 3, 14" F47 and a few chrome extras. Boom crap gone.
2016 RG Special Cosmic Blue, 120ST with Dragos 2:1 and TTS tuner, FBI drop seat kit and JNR air ride. Stock audio long gone.