8" in doors few questions

[micker]

Looking to add some extra bass up front

And look to add some 8" in the doors

And type of sub (not brand) I should be looking for, Like something suited for IB, sealed ported

Power if its not an IB sub is there a rule of thumb like 50 or 75% of rated

Crossovers

Normally I just use the LPF at around 60-100 for subs and no epicentre

Will I need a HPF as well as LPF if fitted it door to stop bottoming out or ......

First time for me to go out of the normal

I normally just amp and speakers/sub and only use the Built in stuff like head unit eq and amp crossovers

[Joe X]

Some beefy midbass drivers usually work well on IB, would likely put some output on the 50s (Hz) up, these type of drivers need to be bandpassed. Best way to do that is with a DSP based crossover which you can buy separately, some head units have it incorporated.