Lecithin contains more than just choline (or more accurately in lecithin's case, phosphatidylcholine). It also contains phosphatidylserine and choline, and some beneficial fatty acids. That's why I use it, although I also use a bit of centrophenoxine as it is definitely better at increasing acetylcholine.
But yes, I would definitely agree that it's a bad idea to start mixing nootropics and psychedelics. I've had one of my two most profound trips mixing DMAE and piracetam, but it was horrendously terrifying and out of control, and I would not repeat it. I've mixed piracetam and/or lecithin with two other psychedelics as well: it made 5-MeO-MiPT feel like the flu and completely unpsychedelic, and it made AMT feel exactly the same (these two were mistakes - I take nootropics daily and I had forgotten that I had even taken them). But many wild and unpredictable effects have been reported from mixing nootropics with psychedelics, and very little is known about it. So proceed with extreme caution, or better yet, not at all.
If you must try mixing a nootropic, however, I would stay far away from piracetam or any 'racetam. In my experience they (piracetam anyway) creates hugely unpredictable and powerful effects.
