I dont understand this obsession with 17" tires on a car designed on 19" tires. Get the correct size equivalent or dont do it at all. 255/55/17 is an exact match and will fit on a stock Mazda 17" wheel.
2.2% is a huge jump. As far as the pothole issue, no, more sidewall wont absorb more shock "by default", unless you run less air pressure which causes other issues. Blown struts and shocks can cause damage to tires when hitting a pot hole, i kept popping the side wall on my 1st Gen till i replaced them and then it stopped.not that big of a leap from 225/55/17 or 225/45/19
Ill answer this here even though i responded in the other thread, since its a bit of a different question. Aside from the coil over suggestion, it seems that for lesser performance needs, Bilstein would probably be the way to go. You could prob reuse the factory springs as well as they would be nicely worn in vs newer springs.or which premium aftermarket setup to go with?