Based on your prior post history I assume you are referring to the top 3 carribean schools, SGU, Ross, etc. I'd always heard 3, I guess these days the kiddies talk about a 4th.
Basically this is yet another thread asking about the Carribean. This topic has been discussed to death, but the short answer . . .
I don't think you'll find a salary difference between IMGs and US grads in the same specialty. What matters in landing a job is your residency, not your med school. So if you manage to get an IM residency, etc and then get a job afterwards no one will say, well, since he went to a Caribbean school we'll take 15% off his salary.
But yes, you will have a tougher time landing a US allopathic residency comming from the carib than from a US aloopathic school. In specialties like neurosurgery, derm, etc the doors (these days) are basically closed.