I have seen the same. Usually the weld solution is less expensive. I would recommend at least 90 degrees, there are some new ones that go over 100 degrees.There is a wild price difference depending on the supplier. I have seen kits as low as $150 and as high as $2K and that does not include install.

I have been toying with the idea for a year now. Not just for looks. The doors are very long (and heavy). If you get stuck in a space where you can't let the door open and hold at the second detent, it is hard to bring your legs in without crushing them. The Lambo action would allow easier access in a tight parking place.