The car will be used on track days, so I would rather have a little more space, as there is a higher chance of stuff happening, only just broke my leg, & i would like to try and avoid it happening again. The reason for asking how far to reduce the size of the tunnel, was that the top of the tunnel houses the gear lever & handbrake, and in the tunnel itself, I will be running brake lines and electrics. So I was asking the question with these factors in mind. Dont worry about it.

Bought some seats from mev the other day
I have made some runners that have lifted them up about 25mm they are tight but they seem to be fine and are working on the sliders etc
They seem to be a good choice for the " broader" person while still giving the grp race seat look