Even though I knew about the car bomb I'd always assumed 'blow up' was a reference to how big he was going to be, which to me makes more sense given what proceeds it and the fact it's in a hip-hop context.
The internet doesn't seem to agree with me though.
That's what I'd always assumed, but I'd heard it/similar line in other songs so intrigue got the better of me and the internet gave me the same answer.
Perhaps it is just about getting big, as the rest of the song would appear.