G403 is one of the best mice on the market currently - but the wireless version is certainly not at your RM200 budget cap.

Honestly speaking? I wouldn't suggest anything under the G403 wireless.  There's a reason why it's expensive, because it's seriously very good - I can barely (if ever) tell the difference between the wireless and wired version, that's how good it is. I'd suggest saving up.

If you want a budget wireless gaming mouse, then I'd say don't bother.

The wireless performance of the G903 is as good as the G403. Meaning they're both fantastic as far as latency goes and that's about pretty much where the objective decision ends.

That said, the only reason to go for the G903 is that the shape and size is befitting to what you want. You yourself will have to decide that. Do you also need the extra buttons on the G903? They are subjective decisions that no one can make for you.