After some research, I've found most mid-engined cars will come round on you if you aren't respectful of them!
Don't think wheelbase is a problem given the lenghts of other mid-engined cars.
And yes, you're right it's a lot of work, not sure it's too dissimilar from trying to go RWD or 4WD.
And also thought about getting another shell instead, think that might be a good idea.
Edit: if I do get this project to the road, I would need to go to an airfield first as I'm no greatest driver and have limited experience with RWD.
Some tuition on track might be wise also