Leo_Cro- Welcome to Autopia!
I've never tried the exact combo you're considering, but here are a few ~random thoughts that might be helpful:
Wax over IHG is a time-tested approach. The wax seals in the IHG so it lasts much longer than it would on its own.
Many/most sealants won't bond well to IHG, it's too oily.
Many/most polishes will clean the IHG right off the paint.
While I'm not familiar with the E1 product, if by "polish and wax" they mean that it has some cleaners in it, then those will probably clean away the IHG (which is easily done).