supertweeter

if I have 4 300 RMS channels and 4 300 RMS 10 inch mids and 6 100 RMS tweeters would said amp still be good

I'm looking to upgrade my speakers in my car, I was looking at an MBQuart OA800.4 thats 100x4, I was thinking of getting either (4) QP-MR6.5's, or (2) QP-MR6.5's and (2) QP-TH25 super tweeters. What do you think would sound better/ louder? I'm afraid the two speakers in the back wouldn't be...