For years, I've been using the transcendental meditation mantra which was assigned to me. Is it OK to do the mantra enhancements with the same mantra? This web site has been great. Thank You all. Since starting DM I've been doing pranayama which amplifies meditation immensley. Also, I've started Samyama, but at a self pacing rate. I overdid it once and felt like the kid who ate ALL the candy.
Welcome to the forum! I can't answer your question. But if you added pranayama and samyama in short and haven't stablized them yet, it is suggested that you take some time to stablize them first before considering mantra enhancement. Mantra enhancement is a big step forward and it is likely to overload you if not well prepared.
I've used a personal mantra before, enhanced several times, but I think it makes more sense to add enhancements from the same school as the first "root" mantra. Nonetheless, the last enhancement made me intermix those mantra versions from time to time while meditating.