So time to make and secure the body mounting plate.
First thing I do is sand the inside of the body flush to create a clean mounting area.


I like using this thicker styrene sheet. Some use basswood, balsa, actual posts, etc. I am just happy with this approach. Sit the body down and trace the outsides. Then trim so that the plate just its snugly on the sides. You don't want it to spread the body out too far. Then cut the center out to clear the motor.

I will sit the body right on top of the chassis with the body touching the tires. I mark the tops of the mount tabs.

Fit the plate inside and sit the body back on. You might need to tack the plate with hot glue as a temporary hold to check the clearance. Install the plate where it completely covers the lines you drew. This is normally a great start and you will only need a little adjustment.
You CAN adjust the right side to create a little body tilt/camber. I do this often.

If the ride height is where you want it, secure the plate permanently with adhesive. Super glue works great as ell as good old Testors model glue.
Now adjust the body on the chassis where you want it to be. Lightly tack the body to the chassis with hot glue to hold it in place, then mark and drill your holes.

People have asked about screws. Well, I just order the Carrera screw pack. It has the longer and shorter screws and they do the job just fine. Plus they work in my Carrera models when I lose them :)

This side looks good but I need to lightly sand the back fender well to make it look right. Little too close. It clears, but I'll still sand it.

I like to mount my bodies with a slight offset. Not too much, just enough for effect.

Yes, looks fine.
Test running says we have a decent car. Time to make it look better :)