Mike - Stepping into a bigger speaker is going to give you more bottom end that smaller sized speakers cannot. The XM9 is 10mm bigger than the REV8 cone/surround wise, and has a bigger enclosure displacement as well. It's not an 8" speaker by conventional We do not use any off the shelf basket, cone or surrounds in it. It's design varies greatly from the XM7 which had a more traditional approach.

In your situation, its all going to come down to weight on your tower my friend.. and how much you feel comfortable putting up there. I did some quick speaker only weights.

XM7 weigh 19.30 lbs
XM9 weigh 21.80 lbs
REV8 weigh 26.20 lbs
I'm not sure what Rev10's weigh

Clamps on all those speakers will add more.

Acoustically either the exile or ws products will get great sound out to your rider. There's no doubting that.

-Brian
Exile Audio