Do worry too much about getting criticized. There will always be ppl who don't like the way you express yourself, just as there will be those who do. It's life.
I believe you can get some custom built for you in this forum. I will not put the links here since it might be misconstrued as advertising.
My personal opinion is that while `burning in' equipment does make a difference sometimes, we cannot easily quantify whether there's any real improvement. If the equipment seems to sound better, it could simply be that your flexible brain has become more familiar with it.

The KSC75, great as it may sound when matched with budget sources, will show up its limitations when input with better material.

The KSC75's have never sounded harsh to me - maybe because I always play them soft to conserve my hearing. But they are definitely bright and sound like the loudness button is permanently switched on! Could this be why so many ppl are impressed when they first hear it?.

Now, that's what I call a mature attitude. Keep your remarks coming, folks!
for what?

I noticed that you have already booked the DIYeden unit.

Did you take into consideration that Eokboy's unit is portable (ie. it can run off batteries) while the DIYeden unit needs a/c mains power, so it is not portable?

Haha, that's a good question. Actually, in my case, I've asked Eokboy to build me the headamp because I want to be able to take my dinosaur with me (almost) everywhere. I don't really need a headamp for my KSC75 because the improvement is not worth the effort of carrying an extra box around.

I can't give an honest answer to this question since I've never listened to it. But the specs are impressive for the price. If portability is not important, then it seems to be a logical choice.
But to buy it just to drive a pair of KSC75s doesn't quite jive. You will probably need better cans to appreciate the DIYeden, and this means you will be caught in the upgrade path pretty soon, like it or not.