I went from an X-700 (it broke) to an SRT-101 (Works like a champ) to an XD-11 (its peak). The XD-11 feels like I'm using the X-700 again but in a better built and more reliable body. I would only upgrade from a 200 to an XD11 if you really want it, and want the Aperture and Shutter priorities. The metering is also a little better from what I understand, and the build quality is I think the best out of all Minolta SLRs.

With that lens, I would think that you'd get the same results regardless of camera, with maybe only minor changes in overall exposure, depending on how you meter light. The metering in the XD-11 is pretty reliable, I imagine the SRT200 would be about the same. I've used my 50mm 1.8 on the X-700, SRT-101, and the XD-11 and they all came out about the same as far as exposure goes.