What are you going to be using the car for Alan?I've got a cusco 6 point for mine and to fit it,you really need to remove the roof lining and carpet to make sure you don't damage them and for mounting.To get these out you pretty much have to strip all the interior and my car is basicly a shell inside.It's no longer suitable for rear passengers(what a shame)and is going to be incredibly noisy unless i fit a load of soundproofing(not likely)
I want mine primarily for handling but after what's happened to the Reyland cossie and Bream's Evo,there an essential safety feature if you're really gonna thrape your car on the track/road.
The best ones are weld in but obviouly it's there for good then unless you have an angle grinder

.Bolt ins are more convenient but not as strong.