Yes
yes it can
The 1975 regular Beetle windshield will fit the 1971 Super Beetle.
Yes I have a 64 and repairing the quarters with 65 skins. They are identical.
No, the M3 has different quarter panels, which are wider then the 330. If you are a body repair specialist, you could get them to fit with some creative work.
Assuming you mean 1973 Ventura, some parts will (door skins and quarter panels, for example)
No.
a 912 Porsche engine will fit in a beetle
The elky hoods are the same. The monte won't fit without changing everything from the quarter panels forward. Not sure about the malibu.
Yes, since that's a tautology. Unless you mean "would additional seats fit in a vehicle without taking the original seats out first", in which case it would be a pretty tight fit, but you might be able to get them in the back. There isn't much room in the "trunk" (which in a '74 beetle is actually in the front), and I doubt you could get them in there.
1965 to 1979 is the same.
It should.. I have a 79 1600cc in my 65 beetle.
Yes, you can attempt to glue cracked Saturn quarter panels back together using automotive adhesive, which is designed for plastic bonding. However, for a more durable and reliable repair, it’s often better to replace the damaged panels with wrecker panels, especially if the cracks are extensive. A DIY job can be done by carefully removing the damaged panels and installing the new ones, but ensure you have the right tools and follow proper procedures to ensure a secure fit.