just need a decent laptop, wifi, and a pass-thru device like a mdi2 clone or others
then you pay the $45 to acdelco tds (this gives you a 2 year "slot" of programming per vin), download the techline software, then once you have the software installed you call techline and request a VCI calibration number to add your upgraded mirrors, presuming the initial flash doesn't automatically enable the mirrors.
hardest part is getting the software installed it might a while you have to be sure everything runs in admin mode including the browser.
they used to have tech2win, sps, gds2 seperate now they combined it all into one platform so you have to get all of it installed for it to work right.
the $45 is only to flash modules.