Has anyone owned an M2 SD and upgraded to an HD camera, but still used the SD M2?

I'm considering getting the SD for my XL2, but then upgrading to an HD camera later this year. Is the $400 extra worth just getting the HD M2?

Scott,

If i'm not mistaken, the only difference btwn the RR M2 SD and HD is the 72mm achromat, almost 400 dollars. The achromat on the brevis is the same thread at 72mm and is known to work on the M2. Dennis wood said its even a tad stronger than the the m2 achromat. AND its much cheaper.

http://www.cinevate.com/catalog/product_info.php?products_id=33

I have bought his achromat separately for my own adapter and its well made.

Ted