Why did you neck down to 2.25"?
Because I hate you ...
But seriously, the mechanic suggested it for back pressure, and I have no plans of putting a power adder on (at least not within the next 5-6 years for sure)
From a few things I read it seemed to me that the actual differences between the 2.5 and the 2.25 were fairly minimal and the biggest reason for a definitive choice (of 2.5") was if the car was intended to become a bit of a powerhouse, whereas I'm really just looking to have a bit more giddy up in my DD. So, when the mechanic suggested it, I had no real reason to insist otherwise.
.. hope I didn't make a mistake :P