Wow! That’s a relatively high price for the GMK87 relative to the F87 Pro!
I’d be inclined to try to search for some stores selling the GMK87 at a lower price. Or perhaps some powerful coupons in conjunction with that.
But the message I’m getting here seems to be that the F87 Pro is strategically priced to be affordable in your region, so it is the more logical choice at present.
It will also require only minimal re-assembly, where as the GMK87 would require more detailed assembly.
Although the GMK87 would ultimately give a better result, it would be more expensive both in time and money, involving a higher level of skill.
Therefore, the F87 Pro is more in-line with your original plans.
You could buy OUTEMU silent Jade Yellow [make sure to get the fully transparent housings, to show that it’s indeed a Jade Yellow] or TTC Silent Frozen V2, etc…
Then, swap the switches in the F87 Pro with the new “silent” switches.
That, I think, is more in line with your present budget and capabilities.
Thank you so much 
Yes. The F87 Pro will be a great start for you.
If you can master the process of removing keycaps and swapping switches, which we can help with here, and it is not difficult at all, then it can be a stepping stone to more serious modifications later.
The F87 Pro hits the sweet spot of price and ease, even if it is not the absolute optimal solution.
Hopefully, you get a good batch of OUTEMU Jade Yellow or whatever. [TTC and Gateron switches are likely to have less batch variance. But Jade Yellows have been pretty consistent so far.]
Try to make sure the store lists the F87 Pro as being ‘hotswap’ in some capacity, so that you can indeed switch the stock switches into silent switches. And that the aftermarket switches are listed as being ‘silent’ or ‘dampened’ in some capacity.
Okay 