That's a really interesting idea. I never thought of it, despite having a Q45 with spoiler and a '93 Max. Assuming the width works, it will probably look great. The Q and Max are very similarly shaped so the spoiler ought to suit Max nicely. I'm sure the contour of the trunks isn't identical, so you'll probably have to use some filler under the spoiler, but it could be made to work.
Some pics of the spoiler if they help:
http://is.rely.net/3-4-12944-l...Q.jpgh ... -l...A.jpg