TR Lane bars:
If you’re tall (and don’t want a full cage, rather a roll bar (hoop) behind the seats then the GP bar would be best. Look at your seatbelt towers and imagine a line across the cabin space from the bolt that holds the seatbelt retainer on, that’s where the bar attaches to. Therefore this bar allows full rearward travel of the seat but may cause some snagging depending on how far back you like the rake on the seat. I’m 6’ and had no issues with either the leather Mk2 seats I had in previously or the current Cobra bucket seats that are fitted. As for cross bracing, t’s as much about form than function. If you imagine a triangle is the strongest shape then the GPX is clearly the strongest (being four triangles formed from the X brace). I have the diagonal fitted to my full cage (essentially the same rear hoop) and I do find that this can partially block the rearview mirror but not to the point where it becomes redundant.
If you want a more track-focused bar then I’d personally suggest the TD bar. This is slightly wider than the GP bar and sits slightly further forward, connecting to the chassis via flat plates that are drilled through the firewall behind the seats, rather than to the top of the parcel shelf floor. Because of its position it can impeed rear travel a bit, again especially if you like a more reclined seating position.
Then there’s the rollcage…
All three of the above are compatible with both soft and hardtops. Some cross bracing will snag on a softtop if you have a glass rearscreen though.
I’ve had all three designs over the years and cannot recommend Tim and his team at TR Lane strongly enough. Great bunch and will happily take on custom builds if you think you may ned an extra inch here or there. A visit to the workshop in Stroud is a real eye-opener to what goes into making these bars and remember steel has gone up in price quite a lot recently yet his prices have hardly moved…
Good luck.