Hey guys, I'm looking at doing some upgrading on the stock Bose system. My current plan would be to go with a nice 200-250 watt double DIN head unit, replacing my front 6.5" speakers and tweeters and put a 10" sub and amp in the trunk. I'd like to keep this on a decent budget, and from what I've read if I go with good speakers upfront and a subwoofer in the back I can just not use my 6x9" on the back shelf, correct? So what I'm wondering is if anything else is needed and whether what I have in mind will work fine, as well as whether or not the stock wiring would be fine for the front speakers/tweeters or if I'd need to rewire those with some heavier gauge wire. As well as what else I would actually need other than a wiring harness and a dash kit?

Thanks.