I got a 8.92 score (I guessed a 9 ex-ante, so pretty good guess).
I'm a purist mainly because having Lego as a hobby means working around the limitations set by the Lego System. Like the Walrus said: where does it end otherwise? I also realize that everyone has a different opinion on what's acceptable or not and I notice with myself that the opinion on this probably changes over time as well. But painting, cutting (even flex tube), and stressing elements are definite no-go's. Also, I don't disassemble minifigs' arms, legs, and hands. Furthermore, I'm more ok with adding custom elements than modifying official elements. But then again: there are only a few customizers out there who make quality stuff that doesn't look out of place when used together with official elements.