Post the three songs you rode to unlock the Stealth Adept, Master, and Legend Achievements!
Artist - Song Title, "Album Title"I simply scanned my music collection for the most mellow songs I could find, in the hopes of creating a track that wouldn't kick my ass while I worked on those achievements. Here's what I ended up with.
Stealth Adept (3 min): Enya - Boadicea, "The Celts" (3:31 playtime)Pretty standard Enya track, very slow and easy to maneuver, there were a couple of tight parts near the end, the only place it gets tricky is about 1:07. If you make it through that, you're over the hump. I find it's still hard to quickly navigate between gray blocks on very steep bumps where you don't have a lot of opportunity to glance ahead and see what traffic is like. Only took a couple of tries to get through this one.
Stealth Master (7 min): Enigma - Page of Cups, "Voyageur" (7:01 playtime)Page of Cups is one of those staple slow instrumental tracks that Enigma typically has in the middle of the album. This one worked out perfectly since it was 1 second longer than the requirement for this achievement. Not too much craziness to report here, it was smooth sailing all the way through...got it on the first try.
Stealth Legend (11 min): Geinoh Yamashirogumi - Illusion, "Akira: Original Motion Picture Soundtrack" (13:57 playtime)My wife seems to think I cheated on this one.

Hey! A song is a song! This is off of the movie soundtrack to the anime film "Akira", and is a standard Kabuki-theater themed track. There really isn't a lot of rhythm at all, and very minimal amounts of music, laced with the traditional Japanese singing...comprised mostly of "Yo! Whoa!" repeated. Due to the makeup of this song, the track was EXTRAORDINARILY slow, and not complex by any means whatsoever. If you want a simple stress-free song to unlock this achievement, here it is.
The pickings were pretty slim for slow, 11:00+ songs in my music collection. If you think this is a cheap way to get the achievement, but still want a reasonably slow, easy song, here are some alternates:
Delerium - Sensorium, "Semantic Spaces" (12:06 playtime)This one was my first choice and is pretty slow until about 7:11, where the rhythm picks up for a few minutes...and I accidentally ate a gray brick. If you can get through that part and hold on until 10:25, you'll be over the hump.
Enigma - Principles of Lust (Sadeness/Find Love/Sadeness Reprise), "MCMXC A.D." (11:44 playtime)This is the 2nd song off the first Enigma album, which is actually three songs spliced together. It's reasonably slow, and could make for a more challenging attempt at the achievement, due to the "boom--boom-cha--boom--boom-cha" rhythm that would keep the track pretty bumpy.