I used to play the amp flipping game and gave up on it. Speakers are where the real difference in SQ is. Compared to the difference in amps and speakers I'll take an upgrade in speakers any day. I'd try those 8's out first and then work on an amp if you feel you need it. IMHO.
I can't buy the RTi8 right now. I need to get rid of what I've got first. Plus the RTi8 won't timber match with the 25c. I think I'm just going to wait it out.