I haven't seen anyone in this forum put in a suspension which appears in any way to be better than the Tesla Model S suspension; that's not surprising simply because the Tesla suspension is a typical modern design for an expensive car. The big reasons that I see to use a different suspension (not Tesla's) are:
- undamaged suspensions are likely less available than the drive units
- buying (even as salvage) the Tesla suspension is expensive compared to using the parts the project car already has, and perhaps even expensive compared to aftermarket components or other salvage parts
- the Tesla suspension is designed to work with their subframe, which is designed to fit their structure; the original suspension of the car being converted fits that car properly
- the Tesla Model S has a rear track dimension of 66.9"; this is relatively wide (because it is a large car), so it is too wide for many vehicles (for comparison, a stock Lotus Evora has a 62" rear track)
On the other hand, there is a long street rod tradition of using the entire suspension from some donor vehicle... to the point that many cars are essentially re-body jobs on some modern vehicle (often a Corvette), rather than upgrades to components of a classic car. You can't really put a Willys truck body on a Tesla Model S structure, but if you have the fender width available you could put an entire Model S rear drive and suspension assembly (everything attached to the rear subframe) under the back of the truck. You could do the front, too, for compatible dynamic behaviour... again if the width works. With both ends swapped, you would have a choice of front wheel drive (no!), rear wheel drive, or all wheel drive. You would also have one remarkably expensive Willys.