Type R comps are peaky in the high range and although they got a lot of midbass, it makes a coloured sound.
Type X's are much smoother, it's worth the extra hundred bucks. Go for the Type X's. Oh, and spare some room for those crossovers.
As for any higher end component speaker set, I wouldn't recommend any without using a separate amplifier to power them. You simply won't get the potential out of them by just running them off a deck. That's what stock speakers are for.
I heard a setup with SPX-137A Type X's running off the deck power off a CDA-9813 and it was gross. It got too distorted at volume levels above 2/3rds.
I'm not sure about the 400S rockford amp, but the setup I referred to used a Punch 360a2 and it was a dirty, dirty amp. I know from experience the 360a2 is a distortion prone amp, the 400S might be fine, but I was just bringing up a point.