2" to 3" exhaust... Worth it?

It's not so much the size as the type of bending. Mandrel bent tubing will have significant performance gains. Since it's quite rare to see 2" mandrel bent exhaust, you will be looking at 2.5" for your application.

An very common example of a 2" crimp (oem style) bent system swapped out to a 2.5" mandrel bent system on a car with 400hp, you'll get easily 35 hp. It's more normal to get 50hp!

Some may not believe it but we did extensive dyno testing for several years on all our Pypes systems and kept getting the same results time after time. Mandrel bent exhaust is like night and day performance wise.