Subframe connectors needed or not?

So you're saying the bolt in type simply aren't worth the effort, or, they are only good for so much torque, i.e. if you go more than 400 lb ft you definitely want the fully welded ones? I ask because I'm considering a 360 magnum crate motor, it puts out 320 hp/400 lb ft. I don't mind the welding, it's just the carpet seats etc. hassle. I saw above somebody did it with the carpet in, I also have dyna mat, am afraid it'll catch fire.

Brian