Would a replica nismo kit be structurally sound if I cut off the center cross member?

 

Probably, but what's the point of doing that? You can get that look much easier by just adding the USDM Nismo lip to your stock bumper; it'll be exactly the same.

 

+1

 

Could have sworn the opening was a little bigger on the V1 versus the stock bumper + lip. More research is needed.

 

Nope, V1 bumper is viryually identical in proportion to the stock bumper; just has that cross bar in the grill and integrated lip. That's why, for USDM, they don't offer the whole bumper, just the add-on lip. V2 bumper opening is larger (taller).