Being a GS500 rider myself, I'd say go with the GS. If this is your first bike, I'd definitely go with the GS. It's saved my ass more than a few times.
Anyway, naked is the way to go. Here's a DIY on removing GS500F fairings. I hear it costs about $200 for all new parts. GS500 Wiki
I'm sure the SV650 will be about the same process, but I don't have DIY for you.