I didn't experiment with any other racetams, especially the stimulatory ones. I found Piracetam to be a reliable, clean effect-producing substance. It wasn't a profound or "Limitless" experience, but it definitely added a good edge to mental energy and sharpness. I did experiment with mega doses based off Isochroma's work and found that it at those higher doses, mania could definitely be induced. But I found most value in the 10g range (technically 9.6g), 3.2g three times a day, and overall stayed away from those higher doses... even though some might consider 9.6g a day higher. The lower doses just did not move the needle for me. I also did supplement with CDP-Choline because you pretty much have to with it. I haven't used it in years, mainly because for a while it got hard to source. Not sure if things ever got better; I haven't looked. I think it's one of those things now, like sleep aids, customs will confiscate without hesitation.
I tried a lot of things during that time.. NSI-189, Memantine, and a lot of injectables and inhalants that were offered by the old Ceretropic (P21, Selank, Semax, etc.). Even tried intranasal insulin. I really didn't experience any kind of benefit from anything aside from Piracetam.