I'm getting ready to replace my Goodyear Tires and need some opinions. They've been on about 4 years and have Michelin Air Stop tubes. Any recommendations on replacement tires (1), and would you also replace the Air Stop tubes at the same time (2). Thanks in advance for the multitude of opinions. BTW, I got 210 landings on hard surfaces with those tires and if I had rotated them at this time last year, they probably would have been good for another 6 months or so.