At what point do you want to add subframe connectors?

After adding my 360... I'm starting to question at what point sub frame connectors are needed?

300+hp? 400+hp??

Thanks!
you will know wen the windshield starts leaking and the door get harder to open then wen you really start to hook with a good motor the doors will start to pop open on take of.there well worth putting in before all that happens.and I wouldn't wast the money on bolt ins.