The stock speaker size is 4". You won't get much bass from that. Guys have put 6.5's in there, but that requires putting 1" spacers in. And even 6.5's won't give you a whole lot of bass, but it'll be a little better the 4's. If you're looking for easy, then just replacing with 4" speakers is probably your best bet. You'll most likely also need to either solder or crimp on some connectors to the stock wiring to slide on to the aftermarket speaker. The stock setup will have a plug style connector for the stock speaker that won't work for an aftermarket speaker. It's really easy! Don't be afraid to try it. Google is your friend, just search this site for door panel removal, pick up some stock sized replacements off amazon/ebay, some connectors and a crimping tool and you're all set. Probably a how-to on here as well. If not, the interwebs will show you the way.