how do i take the old screw studs of my hood louver and what kind of glue can i use for the new one

 

Thats a trick used for folks with a bunch of them busted off n no other choice, I would not cut the off on purpose.

A simple dab of clear silicone in each corner on the under side where you can't see it and it will be stuck down well for many year, yet still come up if needed.

 

I just posted on the Body section on a thread about this but I'll do it here too. 3M windshield adhesive works great on that. Just a dab at every broken stud and a couple of extra dabs in the corners.
It stays rubbery and sticky without drying out all the way. Even here in Arizona. The best part is you can get the louvers back off by gently lifting and breaking it lose with a putty knife.

Of course keep as many studs as you can. With a steady hand hold on to the end of the stud with a pair of pliers (lightly) when you break the nut lose. You will probably break some anyway but it's that initial breaking lose of the nut that kills the stud IMO.

 

It might sound silly but spray some wd-40 on the studs before you try to get the nut off, also hold a backup on stud as mentioned before.