My opinion is you can't get great midbass out of a 5.5". 6.5" at a minimum. You will have to tune the crossovers and maybe use some eq and blend them the best you can. This all depends on the person, what sounds good to you and what your goals are. My wife is perfectly pleased with the 4" speakers in her honda and doesn't like my stereo with 6.5" bostons and 12" sub? Even with my 6.5" I'm not happy with the midbass yet. I need to do some fine tuning when I get a chance. Good choice with the amp. The more power the better. I've been told the 425 x 2 I have on the front is too much, but it is working well.
The pro's midbass is decent. If you're looking for real good midbass response, you could just throw more power at it and tune it accordingly. If thats not enough, you could think about a 3way component set, which has a dedicated midbass driver, separate from the midrange, along with a tweeter. Some of these components allow for the feature of "bi-amping". So you can send separate equal amounts of power to the tweeters and midrange/midbass driver. Sounds quite amazing. I sat in competition truck with a JL XR 3way set with 1000 watts going to his speakers, bi amped. It was just plain amazing.