Has anyone installed wheel studs and lug nuts in place of the overly expensive lug bolts? I have seen them advertised for mounting porsche wheels on VW's and wondered if the application would be the same? If you have any info, or know a supplier, I would love to know. Thanks.

yes lots of folks do just that for a variety of reasons
my current car has screw in studs and I use factory 911 lug nuts that have been bead blasted to remove the black anodizing...
I need to remove them and do a quick bead blast again to remove lug wrench detritus...
Be careful on the type of screw in studs you get...there are good ones (more expesive) and not so good ones (cheap)
Also make sure if you do screw in studs you use red Loctite on the threads that go into the hubs...and torque them properly....then they will stay in place when you remove the wheels in the future.
If you get open ended lug nuts you can then use them on a variety of wheels...like factory Fuchs or factory Steelies without having to get more lug nuts...
I got the proper length studs so I could use them with factory 911 alloy lug nuts.

You can also get 911 style press in studs, you will need to have your hubs drilled to accept the press in studs (more money)

none of this stuff is cheap...unless you can find some of it used here in the classifieds.

I dont suppose that you would know what length studs I should get for rivieras would ya?

I believe Rivs have a thinner mounting flange than Factory Fuchs...
If you are using open ended lug nuts I would get studs long enough for you to change wheels in the future...

check for lengths available here
studs

IIRC I used 52s in the front and 65s in the rear but I could be off on that one..

Here is some press ins and nuts. GPR can order them btw. Talk to Jonathan
http://swayaway.com/WheelStudsAndNuts.php

I did a set of hubs & rotors for my 71 Lightweight, but I used 930 studs so I could use slide on spacers to give a wider track..