Thanks guys for your help, I've decided to get W40 as it is the IEMs that I think about more after trying W40 and UM PRO 30.
@NawiLlih, The replacement upgrade IEMs is not expensive or over my budget so I'll like to get the best possible IEMs I can afford with my budget.
@ostewart, Thanks for your description. I'll probably get a silver cable or silver-plated copper cable to try to lift the veil of the vocals.
Let us know what you think of it when it arrives :)