I think I'm 4w3 and INFJ. I don't think it's very common for INFJ, but it does give me this weird stress between wanting to fade into the background and wanting to be in the spotlight.
I haven't heard of 4w3 ENTP before (have you looked into 7w6 or 8?), but I suppose it's possible if you have very well-developed Fe. Fe can want lots of love and attention from others, and if there is any Enneatype besides 2s that wants love and attention, it's 4w3.