Lets take a step back for a moment, because there's a LOT of mis-information on the hows and whats of amplifying these 301XLF 2 and 3 way designs.
A lot of people are acting like these cabs are similar to Acmes, which with their low sensitivity DO like to have more wattage on tap to get the SPL pumping.
You DON'T need a huge pile of wattage to make these cabs perform. What people are suggesting is that because you CAN push these cabs with big wattage and still have them perform, you may WISH to use a sizable amp. I know, I used my first 15/6 with a LMII and it was still VERY loud. I've been using 2x3015LF for the past 8 months or so with the LMII and the stage volume is tremendous.
I'd suggest that these cabs perform BETTER with low wattage amps in comparison to many cabinets these days. Why? Because there's so little low end roll off, you don't have to push your lows on your eq to get plenty of full bottom end, therefore giving less powerful amps plenty of breathing room before they run out of steam. We know that reproducing the below-the-belt lows eats up clean headroom, so if you get more low with your amp set flat, or possibly attenuated in comparison to how you've set up with your previous cab, you're actually getting more headroom.
Therefore you get 'big bottom' anyway.
Now, while the speaker does list a 'thermal' rating of around 450, the dynamic of how bassists play combined with the mechanical limits of the speaker, and a well designed crossover in a correctly designed box does not equal "this is a 450w speaker"...closer to looking like a 750-900w speaker if we discount that 'speaker ratings' are a fluid notion at the best of times.