Modifying a future classic!

I've been guilty in the past of hacking up my 'precious' plastic crack to recreate a vision of a never to be officially made/pipe dream/released transformer.
But where do you/I stop?
A few posts over the last few weeks, maybe the last year have made me come to think about how customising/modifying affects a figures value.
Modifying something like a mass release deluxe figure is totally different than a Masterpiece in my eyes. I've no problem picking up mass released figures at a discount store knowing I'm going to use them for customs. But when some thing rare or expensive I'd rather leave it 100% original.
I very rarely sell any of my TFs as I'm a very specific buyier of what I'm aiming for in my collection, but I do customs as well.
So where is your balance? Even if your in to the even tiniest modification?
But where do you/I stop?
A few posts over the last few weeks, maybe the last year have made me come to think about how customising/modifying affects a figures value.
Modifying something like a mass release deluxe figure is totally different than a Masterpiece in my eyes. I've no problem picking up mass released figures at a discount store knowing I'm going to use them for customs. But when some thing rare or expensive I'd rather leave it 100% original.
I very rarely sell any of my TFs as I'm a very specific buyier of what I'm aiming for in my collection, but I do customs as well.
So where is your balance? Even if your in to the even tiniest modification?