The Sugino 75 cranks are cheap? News to me.
You can mix-and-match JIS and ISO square-taper cranks and bottom brackets, but it's not a great idea, and it can mess up your chainline since the larger JIS taper crank will slide further onto a smaller ISO-taper bottom bracket spindle than an ISO-tapered crank.
If you want to upgrade to a 170mm crank and are going to get Sugino 75's, just get a new JIS-taper bottom bracket as well. You can get the Sugino 75 bb (109mm symmetrical spindle as baxtefer notes) or a Shimano 107mm square-taper BB. 110mm Shimano bb's aren't symmetrical; the drive-side axle is the same as 107, but the non-drive-side axle sticks out an extra 3mm.
I'm pretty sure the Sugino 75's are JIS taper. JIS is the Japanese standard that was adopted by most of the industry; ISO taper is only used by Campy and a few other European makers (e.g., Stronglight).
__________________
"c" is not a unit that measures tire width