Indica vista - accessories from dealer

Hi

Is it advisable to get the remote locking for aqua tdi from the dealer itself. And also the music system. I was told that the warranty and extended warranty will be void if any electical (music, rear power windows etc) is done from outside shops? How much its true?

Is any use of taking extended warranty for next 2 yrs (2+2 yrs) from dealer?

can someone help me,i want to fit doorvisor{rainguard]and spoiler for my vista please help me which one is better ,GALIO visor is not in market now there is only PAVAN and AG brand ,i think this pavan and ag brand is not good ,is it advisble to buy those brand?cost appmtly 1000rs