Well my personal view is that the 2 3/4" would suit you well re torque.
Not sure if someone has already mentioned this but an exhaust system does not make much, if any, difference to EGT, this is done by increasing boost, bigger/improved intercooler, EGR block (although the text books will tell you differently about EGR block, on mine it made around 25c less), in that order, yes a bigger intercooler scoop will make a difference but my old DI still has the std scoop and I rarely see anything above 450C, the colder the air going in the cooler it is coming out. My CCIC has very good efficiency, when I first fitted it years ago I tested and found that on a 38c day I had 48c at the IC exit. personally I think a good fan under a good IC will make more difference at lower speeds than a scoop, one reason I have not taken that pathway yet.
If you want to go the next step you can fit water injection that fires under load and makes another improvement.
Just don't expect too much from just fitting a better exhaust.
My 2 cents worth.