Everyone has their favorite machine, but usually people choose more easily controlled machine or the fastest. Personally I like to drive with RAC, but on many tracks LX6 is the fastest and on some tracks FZ5.
Why should You delete that KY3R replay... Do you think that your KY3 replay is clean ? ...not so clean. And a lot of replays are not so clean, for example Kyoto Oval MRT-cutting turns. And KY3R T1 is cuted almost for every WR. So better save it and upload, coz a lot of drivers are driving dirty.