What practices can aid (or not ruin) the mahasi style meditation?

This question goes specifically to theravada insight practicioners - but everyone can answer if they think they have something useful to add - even from other traditions since my mahasi style practice is going slow and even though i tried in many ways i cant maintain a steady practice - and my doubt increases - i want to freshen up my practice - maybe get some "results" wheter its improvement in concentration or metta or some "cool" results like seeing images or feeling strange stuff ect i wonder : * whether some practices can ruin my main mahasi style practice (which i want to keep as my main path cause i have access to teachers in it) maybe kundalini and third eye and stuff like that can ruin my practice ? * whether some practice can aid in my practice - im pretty sure metta can be helpful but maybe pure concentration focus can distract me and do more harm than good to my practice ? * i read that some food can be good for opening the third eye - can this food be helpful to the practice of insight meditation as well ?