modifying compression driver's exit from 2" to 3"

[elac310]

Hi all,

I have some horns with 3" throat and was wondering

1) whether JBL 2490 (and to some extent Community EM 280 / EM 282) are the only 3" exit drivers available on the market?

2) whether one can mod a 2" exit drivers to match; I know that normally, an adaptor would be used but: is anyone aware whether there are some 2" exit drivers that can be adapted by widening the size of the exit (or are all drivers' throat designed in such a way that this idea is pure nonsense)?

Thanks for all serious and informed feedback.

Chris.