Hmm... now that's interesting... Since Yukkuri seem to like Pet Clothes, would having "improved" accessories be better for them? I know this Marisa's freaking out, but now I'm wondering if other kinds of improvements, like needle work for example, would be like a status symbol?
I think "less is more" applies to modifications. Small aesthetically pleasing changes would definitely be seen as a status symbol, hell, that's what badges are.
The yukkuri probably wouldn't react that well if you tried to seriously modify it. Hell, they might not even recognise it afterwards, or interpret you as damaging the accessory...