I have 95s in mine, its honestly just preference of how you like your car. I hate cars that you cannot feel anything in, I like the rattles, bumps and noises, it helps you feel what the car is actually doing. The 60s should be just a bit stiffer then stocks which is completely fine and will reduce wheel hop significantly.
Are those just mufflers or a whole system? You wont get any "pops" with just a muffler if that is what you bought. You also wont have any rasp if the rest of your stock exhaust stays in place, the stock system is incredibly restrictive.
You will be fine with the mounts, you will feel some vibration and a little less after they break in.
As for the exhaust if it's a full exhaust you will not be able to tell on how far the tips will stick out until you get it on the car. I had comptech exhaust on my 08 civic si with the same style of tip and it did stick out more than other exhaust I had seen but it was not super crazy. Once I added the lip kit you could not even tell at all.
Not much louder to be honest. The header, cat, and massive res cut down on 90% of the noise. You might get a little grumble.