I reread again and see you are after an "ultra thrower". Are you sure you want an XM-L then? For a serious thrower you may wish to look into very hard driven XR-E's. You can pick up some cheap budget ones like the Super Tactics Q5 thrower that so many BLFer's love, the newer Jacob A60 (also see here), and the one I have - the Dongrui All-920 (better beamshots here). My vote would go to the Jacob A60 for now. The pill in the Dongrui isn't so good for long term use.
-Garry