The GT6 and Spit frames are nearly identical. Yep, nothing like a mundane bread n' butter Herald frame with some sexy Italian designed tin wrapped around it.
I've already reworked the Abomination's frame and steering rack to fix the bump steer and Ackerman.
I cut a stock steering rack and rewelded it to get the length right. Due to various concerns about mounting different odds and ends the rack itself is shortened compared to the housing, this cut the steering from ~ 2 3/4 turns to ~ 2 1/4 turns but it seems not to have affected the turning circle. The bump steer is about 90% gone, to get the rest I'd have to make the tie rods longer which means I'd have to heat and bend the steering arms on the knuckles. The Spitfire and Miata knuckles both have the outer TR real close to the rotor so that would take a major rework of the brakes to fix that. Or I could lower the steering rack about 2 1/2" and flip the outer ball joints over (that's because the Miata knuckle's tie rod mount point is angled) but that puts the rack dead in the center of the frame meaning a complete rework of everything forward of the firewall. Not worth it for the little bit of bump steer that's left.
The Ackerman thing involved notching the front of the suspension towers and scooting the rack way back. I made a bolt in crossmember to strengthen the suspension towers but the only reason I could do that was the 12A is shorter than the stock 4 banger and could be mounted further back. Otherwise the crossmember would go right through #1 cylinder. Due to the Miata knuckles I also had to raise the rack 1/4". I used a set of the aluminum rack mounts while I was doing all this, man it steers nice now even in extremely tight turns.
All the hard figgerin' is done, I just need to duplicate it on the GT6 if, as and when.