I would just do everything at the same time. If your going to amp the doors make sure to buy or make some crossovers for the tweeters that way the door speaker and the tweeter will be amped. This will also imporve the sound.

1999 Silver Frost Contour SVT 2690 of 2760 Born 08/13/1999 Sony Mobile ES CDX-C90 Deck 6 1/2 Infinity Kappa Perfect mid & tweet set, 2 12 Infinity Kappa Perfects JBL P.600.1 for Bass, P.180.2 for front stage.