I recently put an EB 60 Mega Ray in a 4x2x2 enclosure & I'm using 100 basking flood to get the temps correct. I have 2 other 4x2x2's with
SB 100's in them, the basking temps are good(no other lamps for heat), but they heat the whole enclosure. I have removed one sliding glass panel & replaced it with a sliding screen door, just to have proper temp gradiant. Check out the EB series lamps, my little female is growing like a weed, basking under a EB 60 MVB everyday.
to answer your question, IMHO yes a 275 watt MVB is to MUCH for a 4x2x2 wood & glass enclosure
something else to remember, MVB's have a minimum distance , depending on the particular wattage & bulb. The one's in my enclosures are @ 13"-14" above the basking area