In a Pantera, the best seat to use IS a PANTERA seat. The weakness of them is the STOCK track system.
If your car is a one person driver car then even those are sufficient.
IF you happen to have lowered floor pans, I would recommend using Corvette power seat platforms. They will give you the simple option of moving around on long trips.
It would seem though that the strength of this masochistic tendency of some owners to deny these simple facts, should be left to run it's course in order to prevent violent retaliation against innocents and foster public safety.
It just seems so obvious to me though that the Pantera at times seems to be a poster child for contraries and anti-establishment themes? It's like a magnet for them? Yikes!