There aren't street rod laws in NJ that I'm aware of.

We have commercial and consumer tags...
rebuilt/special/kit car tags
antique tags
trailer tags
and of course, antique tags.

Passing the stability test isn't a big deal, I've done it in the past. The key is to add a little width to the tires as you go up, which makes sense because I can't think of a reason why someone would want to go up 4-6" and use 4" wide tread on their truck

Vijay - do you have tools? Installing a lift kit isn't too bad of a job if you have friends helping you. You'll find a lot of shops steer away from such work just because of fear of liability issues.