Honestly, the best option depends on your goals.
If you must do it ALL yourself, automotive pressure packs are a good option, just allow plenty of drying time and plenty of clear coats. The great thing about this method is that as long as you have enough clear on the body, any imperfections will rub out and polish upto a nice gloss finish.
The Best way I feel by far is to paint in Polyurithane 2 part paint. Its expensive to buy in bulk and you need special equiptment to spray it but the finish is TOUGH and you'll get a beautiful deep gloss. An option for this would be to prepare the body yourself, and take it to a Automotive refinisher. As long as the prep work is done and all they have to do is hang the body and spray it, it shouldnt be too expensive. You can pick any colour you like and they can mix it for you.
The other bonus with this is that you dont need to remove all the original Poly coating from your original guitar. Completely sanded with 800 grade wet/dry, the original coating makes for an excelent undercoat, and you dont have to worry about grain filler and such.