Re: 6x9 box?
Yeah, don't enclose them. You'll lose tons of bottom end response. My friend did this with a set of Kenwood 5 way 6x9's (which actually had very decent bottom end for being driven off HU power and a bit of EQ) in an old Accord he had. I kept telling him to mount them in the rear deck and not mess with boxes. He didn't listen, and the music suffered. Since he had a cheaper set of Pioneer 5.25" up front, it sounded like these were the only speakers doing all the work. The rears sounded like they were just producing high range, which sounded like complete crap.
You amping those Type R's?
2011 Kia Optima EX
Factory HU + Speakers
Front Comps - Blaupunkt Vc660 | Sub - Infinity Kappa 800w IB
5ch Amp - still deciding
Bought from: jacobcopeland87, 95bat, alxmlr789, na_rsx