Moss sell 15in wires for the MX5 and they have the relevant spacers built in to move them further out under the body, they are not cheap though at £460 each plus they are 7J and as such you cant fit narrow (period look) tyres as minimum width for 7J is 195 (google search car bible and section on wheels and tyres). The other thing of note about these wheels is they are VERY heavy so if you are looking for out and out performance rather than 'normal' road driving you may want to look elsewhere. I note a lot of people have gone for the 'Dunlop' steel racing wheel look and I believe these are quite cheap, circa £40, and Stuart has recorded somewhere on the site that some BMW minis come with steel wheels that folk are giving away (not seen this anywhere though). Had I not bought a set of the bolt on wires when I got the kit I think I would have been looking for a conversion kit to put knock on wires circa 16in on mine but having spent a load of cash on the wires it will be a set of 195 65 15s on the same for my car.
Cars in the Workshop Replicar - 1998 Mk2 1.8 donor Honda Civic Coupe SR Discovery TD5
Wheels and tyres are a very subjective choice. Personally, I'm going for a slightly different look for my demonstrator as I want to differentiate it from that of Stuart's previous demonstrator so as to give Replicar my own identity. With that in mind, I've gone away from wires and opted for 15" x 7J gloss black steel pepperpots with 205/60 Dunlop Blue Response tyres (I like fat tyres -probably influenced by my previous Cobra build.) May not be everybody's cup of tea - but I like 'em. Also, a complete set of 4 wheels and tyres was the same price as one wire wheel without a tyre! Admittedly they will need hub-centric spacers (the centre bore is 67.1mm compared to the 54.1mm of the mx-5 wheels and although the 205's help fill the rear arch nicely, the fronts could do with a 15mm spacer to do the same - so will speak to Freaky Parts at Stoneleigh to see what they can come up with.) Unless you're absolutely dead set on wires, then for similar money you could look at Image Split Rims style 46 (Dunlop alloy replica) which can be made with whatever PCD, diameter, width, centre bore you require. You can also add bolt-on spinners if you so wish. Should be a lot lighter too! www.imagewheels.co.uk/billet-46-classic-build-alloy-wheel/ They also do a pretty convincing alloy wire wheel look-alike but its only available in 16 & 17" diameters www.imagewheels.co.uk/db3-alloy-wheel/