I recently found out that in my country, R3 comes without ABS system. I wonder if i could install ABS on a non-ABS-R3 or not?? And in case that i could, how much does it costs? I would appreciate any idea of you. Ty.
It can be done - it's just a question of how much time and money you have.
Stock (non ABS) ECU may need to be reflashed or replaced to support ABS - or it might be a standard ECU that works with or without ABS - I don't know.
You'd have to mount all the ABS gizmos on the non-ABS bike (sensors, wiring, brake calipers, etc.).
The non-ABS wiring harness may or may not support ABS - again, they may have used a standard harness for all R3's regardless of ABS or non-ABS - don't know the answer there, either.
Get a service manual with wiring diagrams - I'd start there to see what is supported and what is an easy swap-over.
But I'm with Aufitt - ABS is a crutch, in that there may be situations where it helps, but that rider skill and awareness are more important than gizmos.