whats the difference between a d16gt to a d15

[hithere]

if I am looking to cop a Tom Petty/Ryan Adams acoustic feel.

I was going to get a d15 cutaway with the electronics because thats what I thought I could afford, but I am very limited on my money right now.

I figure I can I can do the pickups later because I am very leary of the things, I have yet to find even a pro who has a plugged in tone that sounds close to being unplugged.

There are good systems that require no drilling correct?