probably spoke to soon, its not the vibration (although the crappy roads do that too) but the position of the mirrors makes it hard to see out of them. They vibrate a little but comprable to the 250.
I haven't tested, but im pretty sure it'll do 75 in 1st gear. I usually cruise on the highway in 4th at about 7k ? can't remember too well.
As for suspension, a local forum im on all say Cyclemall does a great job on suspension and the guy Tige explains everything while he does it. I don't have the tool to move the springs (yeah it can be done with a screw driver and a hammer but still) so I probably will just take it to the shop. and plus none of my friends ride, or are mechanically inclined at all (im 17), it would probably be a disaster lol