[MPWR]

there's also going to be a bmw 2 series gran coupe, another sedan that will tap into 3 series sales.
i doubt there will be a big impact on 3 series sales, the 3 series does have it's demographic, one that will differ greatly for the 2 and 4 gran coupe

 

[MPWR]

the 2 series gran coupe is smaller than the 3 series from what I know.

Being a bit smaller might be what some people who were originally looking at a 3 series might want. Plus the 2 series gran coupe is a coupe-like 4 door. Coupe-like styling, a slightly smaller cabin with a lower starting price will attract some potential 3 series buyers.