As said already, Spoof Chip and Morphing Licence Plate are essential. I'd personally also recommend that whatever tires you get, you get them as runflats. For bare essentials of a getaway bike, you want all that plus Increased Seating so you can carry a buddy and still have top performance, Gecko Tips so that you can drive up walls, Manual Override for cheap Matrix security, 1 point of Concealed Armor because the Mirage isn't one of those vehicles that can get away with Obvious Armor, Anti-Theft System 2 so nobody steals it, Oil Slick Sprayer and Road Strip Ejector with Spike Strips because when you use the Spike Strips first they're a pretty good 1-2 combo and finally Gridlink Override so that you bike can break the speed limit even when you're not on it. The whole kit will run you up 25,500 nuyen including the baseline bike (but not including any Metahuman Adjustment you need to make) which is 3 times cost of the baseline Mirage, but trust me it's money well spent.