[stephen low]

The narrowing in my case is to make them fit the oddly shaped G-Force cockpit. As was mentioned, you are battling the widening trans tunnel where the front / mid part of the seat would be but the G-Force also runs an elevated edge around the general cockpit area so you step up from a narrower floor footprint to a slightly wider area atop the lip.

Just makes seat set up in the G-Force a bit messy and limiting. This is about the only major gripe I have with this kit but the issue was overcome by a narrower seat profile. The seats measure 480mm at the rear of the seat / upright corner and the seat side rails spring out slightly to 490mm wide before narrowing again at the front.

Any current car seat is going to be able to pass engineering, the manufacturer did that at start of their car design process, you just need to find one that fits if you aren't going to modify them, and that's the good luck factor.

After the fact I reconsidered what car seats might have worked, some suggestions are seats from:

Suzuki Mighty Boy
Merc smart car
MX5
Original mini frames

But the answer is above I think, a set of PACE frames, even if these have to be narrowed should get you an engineered article to satisfy your build engineer.

All part of the wonderful research phase.

Will be keen to hear how you overcome this.