I would agree with some of the other comments and get a dedicated thread Supernova. Exserts never run as true as a chuck on it's own and the additional distance from the headstock means you are putting more leverage/stress on the bearings, especially if you are not using a tailstock. I suspect you are like me, a large part of my chucking investment is in the jaws and accessories, some of which are home made, not just the chuck body.
Are you absolutely certain your chuck is a dedicated thread model. If not, you could look at lathes that have headstock spindle sizes that can be adapted with an insert. I use a Nova DVR with 1.25" x 8tpi and that is good and solid, and not that much smaller than the M33 x 3, but is available as an insert. To be honest I don't see why some of the latest lathes are using that size thread as I think it's totally unnecessary.
If you do have to change chuck, it might be worth calling Record Power, as they may have a chuck body on its own they could sell to you.
Hope that helps,
Paul