Can only find 100/90-18 (56) for the front. Not sure if those will fit or upset the handling. any thoughts?
I've ridden with a 100/90 on the front. I did not like it. The handling is much sharper with a 90/90. In this case, that would rule out the Pirellis, if you had to have matched front and back. I'm about to get a new rear tire, and a front very shortly. I'm thinking Avons. In the other active tire thread I posted a link to bike bandit showing tires that were available in 120/90 18. Of those, the metzlers and the battleaxs are similar performance wise. Realistically as someone else mentioned, if you're pushing your R65, the last thing to fail or be outside it's performance range will be the tires. Including the rider.
In short, pick a tire that you like the tread pattern, size, and cost. Then go ride!