EEEEEEeeeeeeeeekkkkkkk!
No Way!
Lots of ways to do this, but if you want versatility & solid/safe way to install 4/5/6 point harness, let me know. Mine has been inspected by other SCCA tech inspectors and approved for SSB road race -- if I had a roll cage. [Double eek on cost, checked on a used cage, after shipping & install, could buy a 3.0 to drop in, almost.)
Bottom line, you want to mount to body (welded in) structure designed for lateral streess. Wnna see my installation -- PM me, but expect a wait for download of files -- pics are pretty big for clarity.
Bottom line, later models with third (middle) passenger 3-point shoulder belt have a built in lateral stress-designed area, the sandwiched steel package tray to which the belt retractor mounts. Anybody who has ever looked closely at 3-point (standard cross-chest) seat belts, can tell you that is where maximum thrust/inertia fctors are going to be at play.
Drill a couple 5/8 holes either side of retractor assembly, leaving enough room for standard 2.5 inch SCCA backing plates on each blow and the 1.5 inch washers above, use snap clips and 5/8 eye bolts, and BINGO! You're home free! All hardware can be got at any serious racing parts store -- all mine came from Racer Wholesale, along w/major brand 5 point. (tunnel belt installation is also a snap -- but that's another story . . . ,)
By the way, have you ever noticed that your stock 3-points are screwed (5/16 I believe) into the seat?!?!/ [And the the retractor hold-down, of course.] That means if your seat jumps outta the track, ya better hope & pray the airbag deploys, 'cause all you're gonna do is pivot into the steering wheel otherwise!
Keep smiling.
