I'm going to replace a Shimano 52-39-28 (small ring was changed from original) crankset on a touring bike with either a 48-36-26 or 44-32-22 Shimano crankset. Everything is 9 speed so I'm presuming that derailleurs already on the bike (105 front and Deore back) will be compatible.

1. It looks simple enough to do myself but I'd need a crank puller and a torque wrench. I'd likely never use the crank puller again and would likely use the torque wrench only occasionally. Is it worth buying the tools or is it better to have a shop do it? (I also recognize that a shop will give some sort of labor guarantee.)

2. What would be a reasonable shop cost?

3. The difference in granny gears would be 20.8 gear inches v. 17.6 gear inches. Will a 3.2 gear inch difference be barely noticeable or will it make a huge difference? (Hills and I don't often get along.)

Your input is appreciated.
Thank you.