How low without z the frame

[Twistedsteel]

I am wondering how low you can go without z the frame. I'm not totally against it but if I don't have to......on the other hand if it's easier to z the frame than goin another direction than I'll be z'ing. I am going to go with a Porterbuilt dropmember and run 22's. Sorry for my ignorance but I'm tryin to gather as much info as possible before I start my project. I don't want to do things twice or thrice.
Albie