Ian - I have 15" Rota Grid V's on my MX250. Have a look at page 9 of my build thread:
http://www.madabout-kitcars.com/foru...?t=4179&page=9 The main driver for choosing these was that they are a zero offset so no need for spacers.
A word of warning, I bought 15" diameter 9" rims for the back and finding tyres to fit this rim is a bit of a challenge. I ended up with BF Goodrich tyres which are not the cheapest option. Also, you will need to do some work inside the wheel arches to avoid any rubbing on full lock at the front and bottoming out at the rear as they are a 60 section tyre.