Pulled the trigger a few months ago and put down a deposit on a MK Indy R kit from http://www.smartsportscars.com/
. I decided to delay it when I found out MK were going through some modifications to use Miata running gear. It still uses a Ford Sierra steering column and a Ford Escort rack, reportedly a quick rack with 2.3 turns lock to lock. This past week I heard the kit was ready and about to make it's way from England to Phoenix, AZ so I paid off the rest of what I owed and now I'm waiting. Paul Smart sent me some pictures from when my kit was displayed at the Stoneleigh show in Coventry, England so it's famous already. Apparently, this is one of the first Miata based Indy's and will be the first to make it to the US. It's unlike me to buy the first of anything, so we'll see if I made a mistake.
The plan is for a reasonably fast build and get it running with a stock 1995 1.8L Miata motor and transmission I have in stock then to tinker with it. At this stage I'm not going to even go into the grandiose plans I have for it, I'll just let it develop when it's built.
It uses a modified Miata differential. Modified in terms of how it's mounted. The 'wings' were removed and the chassis has tabs to bolt into the back and there is a plate attached to the frame that the front of the differential bolts to. The uprights, hubs, brakes, etc. are all standard Miata parts and the rest of the chassis is the same as any other Indy R. I'm hoping this means it'll go together as well as other Indy's I've read about.
Here's the pics from the show: