first off, there's a specific thread just for requests.
second off, there's already rips of the soundtrack on here.
lastly, the 3DS version is probably going to feature all of the same music, if not less. I don't know why you would care so much about it since odds are it's going to always be in less quality than your average MP3 as well.
For the original S&ASR, the DS version had a soundtrack that sounded different. It sounded arranged on similar-sounding instruments, as if a sequencer was playing it and they tried to be as verbatim as possible. Apparently Sonic Colours soundtrack didn't have this treatment though... I noticed so I wonder why it happened to the original S&ASR - was Sonic Colours only on 3DS and this changed with 3DS? In that case, then it would be less worth it to me. Or perhaps the "sequencing" is still optional or is implemented when space is needed to be saved, and I think but am not sure that SUMO had trouble putting it on 3DS (and now having an even harder time on mobiles).
I suppose that there is another point of interest that the 3DS version apparently has some tracks "lessened"...
Sonic & All-Stars Racing Transformed 3DS: The Forgotten Version (
http://forums.sega.com/showthread.php?503806-Sonic-amp-All-Stars-Racing-Transformed-3DS-The-Forgotten-Version) don't have two songs or they don't play properly as they Should (I didn't hear Super Sonic Racing in Ocean View), etc...
edit: I just realised that Sonic Colours DS is still significantly different from the Wii though. It has exclusive tracks (special levels, wisps, bosses, events, etc.) and therewith lacks some that the Wii has, and even for the tracks that sound similar, you'll notice that they're not copy-paste because they have significant differences themselves too (I've noticed instrument volume balancing, instrument panning, slightly or somewhat altered instrument sound), and many of the levels have tracks that only share a "theme" or "style" but are different in other aspects.