Thanks!
Yeah I can tell you how I did it, it wasn't too hard actually. For me I made it a little more difficult on myself because the e46 seats have super wide track width. Next time your in a 3 series from early 2000s take a look, they sit basically on the floor so the tracks are outside the seat. So whatever seats you chose pay attention to that because the A body (mine anyway) has a large bump in the floor on the outsides where the bench mounts to. I think a narrower seat track width would be able to fit inboard of this bump and still be centered on the steering wheel.
So I used the factory bench bolt holes on the outside near the doors because the floor is reinforced there, by drilling a new hole at the rear of the seat track on the Bmw seat. So no modifications to the floor there, then I lined up the inside holes where I wanted them and drilled the hole there. Ideally I would weld in some reinforcement plates for the mounts near the trans tunnel but I used some large fender washers because I didn't pull the carpet to do it (no way to weld with carpet in). Unfortunately because of the bump in the floor at the outside front mount that I mentioned the track on the front inside corners wanted to be a couple inches in the air. Currently just have some washers stacked up but eventually will make some better mounts. The bump also makes the seat tilt a bit backward on the bottom but I used power seats with some adjustability so it gets rid of most of that.
