Andrew the Vixen SXW is primarily a visual mount, it can be pressed into duty for short focal length astrophotography with the small, fast refractors up to 80 or maybe 100mm aperture. It is not suitable for long exposure astrophotography at focal lengths > 700 mm.
If you want to do AP don't go in cheap hoping to upgrade, all you will do is spend about double what it will cost if you face the real cost and buy a decent setup from the outset. If you aren't prepared to plunge $10k and possibly $20k on it, don't start.
There is an old rule which IMHO still holds - the diameter of the worm wheels must be at least half the aperture of the scope. Otherwise your mount will be inadequate. The SXW is little more than a fancy toy in this respect and the EQ6 no better. The GM11 is a start, but only adequate.
If you are serious the starting point for a VC200L is a mount from Astrophysics
http://www.astro-physics.com/ or better.
The reason I stay clear of it is that there are so many with more time in dark skies that I may as well not bother, and wait till they post their shots on the net.