all the mod does is to provide the power to heat up the coils. certain juices taste better when using a higher wattage. some juices taste better at lower wattages.
and also agree with what
KenshinAdryan said, the type of tank/RDA used will also affect flavours.
to simplify it, there are many many variables when it comes to vaping. best advice to you is to stick to one juice and play around with the variables that relate to the tank/RDA. once you find the best set up for your preferred flavour, then change the juice and you should be good.