Re: 6x9s or 6.5s?
Pioneer REVs perform quite well off HU power and can greatly benefit from an amp later on down the road. They get pretty low (I heard a pair of 6x9 REVs off 22wpc rms on a Pioneer HU and I could actually feel some bass hits in my chest a little bit).
Check pricing at onlinecarstereo, sonicelectronix, and cardomain. Might be able to get one of them to do their price match guarantee.
2011 Kia Optima EX
Factory HU + Speakers
Front Comps - Blaupunkt Vc660 (active) | Sub - Infinity Kappa 800w IB | 5ch Amp - still deciding
Bought from: jacobcopeland87, 95bat, alxmlr789, na_rsx