I think it's a great idea, driver training is also a great idea but after you have a lesson you can put it into practice in the track pig and test your limits with less worries about what happens when you find them.
A stock MX5 is also a good car for what you want as you say not the power or speed of the Zed but well balanced and great to learn in - I've had some great fun in an MX5 on track, if you can afford it do it mate, I don't think you will be disappointed
As above speak to Ekona or look up his thread he did a lot of work on his but you don't have to go that far