I have only seen 2 MS3's. One was for sale and the other one is owned by a kid i know. The funny thing is when i met him, we passed him and he turned around and followed us for about a mile to my friends house. My friends were saying "hey i think that guy in the speed 3 is following you!" It was funny. Then we got there and they asked if it was a redline so i showed it to him, but i made him show me his car too. I really liked it, They look so cool, most people dont pick out the distinct differences between the regular 3 and MS3. But as far as MS6's i havent seen any.
Edit: Oh yeah, my friend is planning on getting one this summer too