If it's a cheap sports car you are after then buy a cheap Mx5 strip all the heavy bits off then...bingo!!!!!! a cheap sports car that goes round corners:)

Mark,

I have an mx5 in the garage which I am planning to sell to help fund the roadster. I want the satisfaction of building it, as its easy to modify an existing vehicle. I love the styling of the 7 type cars and the fact that they are so simple and light.
I am a qualified mechanic and painter so can tackle most things and I have a huge workshop at home doing nothing.

I am swaying towards an mx5 doner(mine to good to break I think. But mot Sat) as I think I can use seats etc as well as it having good performace and great tuning ability. I could do to see a pinto and mx5 roadster in the flesh and on the road to compare.
I think the resale value of the bits I dont use will be higher on the mx5, thus bringing the overall cost of the build down. If I went with the sierra route, the leftovers would likely be scrap.