In answer to Iain's Question,Yes issue 22 has passed but have a look on E-Bay, there are dozens of those GX-12 Engines brand new on there, I won 2 of them both for £26.52p each. But as stated above you will need to buy the carb bit separate as it does not come supplied with the engine, unless you buy the lot brand new in a shop and then you are looking at £149 for the complete engine (That was the price when I last looked)
And in answer to Josh's Question, Have a look on the Hpi site for a BMW shell...they do make one but you want to make sure it fits the wheelbase on your car, which incidentally, is 265mm.
Here's the link,
www.hpieurope.com ...it's the 200mm wide bodies you should be looking at.
According to Hpi's site they fit most popular makes of car....Check your local Halfords to see if they have them in stock...my local branch does.
Regards..........Mark