relays or diodes?
 

to go from the remote starter to car lights (so they go on with remote start) i was told i need relays, but another person told me he used diodes insted, now both work, but what is the best way of doing this?

What car is it for?

2004 aveo 5 speed manual, with power everything, it has 2 light circuts for left and right side lights. both will work (relays and diodes), but which would be better to use

find the parklights and use that instead.you may need relays to switch polarty.If you don't know how to do that then you should seek a professional installer.

Or you could just use the negative wire.
PARKLIGHTS NEGATIVE brown or brown/dk. blue (-) @ headlight switch

All the remote starters that I've ever used have a negative parklight output.

You can use the negative at the switch if you want but diodes would be enough if you go the way you posted about.