There's an electrical shop opposite the Shangri-la hotel in Chiang Mai with a wide range of LED bulbs for bikes. It's easy to find, and they're a helpful bunch, too. They should be able to sort out your bike, for less $$$ than the Kawa dealership. A relay should cost around 200-300 baht, LED bulbs there were a few hundred baht when I last checked (less than eBay).
As for resistors, on older bikes two diodes are required to isolate the indicator light when converting to LED bulbs. They stop current flowing from one side of the indicator circuit to the other side, and hence stop everything flashing together (??!). On a modern bike, conversion to LED's may be anticipated in the circuit design, whereupon additional resistors may be required to compensate for LED's lower internal resistance.
On reflection, it may be that the Kawa "relay" includes the diodes and/or the resistors. Best to check them out first.