You'll gain a few hundred feet per second of velocity, but ammunition will be well nigh impossible to find and if there's any sort of irreversible modification done to the gun, then the gun's resale value will almost certainly take a hit.
The conversion consist of changing the recoil spring to a 28 lb. spring and changing the slide stop. As far as resale I'll let my kids worry about that. The ammo wil be handloaded by me.
and the question on ..why? no need to buy another pistol in 10mm when a 45super with just a few parts changes ,will do same or better performance with handloads.
Actually ,if you just want to shoot 45super occasionally, there is no need to change any parts on a steel frame .45
Read the link and see the advantages of replacing the firing pin stop in the 1911. This alone is plenty for occasional 45 super firing in your 1911