I would suggest making a clear objective to pursue first. If you spread your effort over 3 goals: Performance, Appearance, and Audio, your results will be in a long constant state of flux where none of them are "complete" until you're homeless. LOL
I listed the 3 in order of my priorities, but it sounds like audio is big on your list, and I think the Sonic will lend itself well to a bad-ass sound system. (relocating the rear speakers not being overlooked.)
Tackle the audio first so you can put it behind you and move on two the other two. One caveat: get the tune before spending a dollar on anything else, including audio.
If you do ever decide to do the CF hatch yourself, I'd be glad to walk you through it.