Header Ground Clearance

Hi, my question pertains to changing my 2-1-2 exhaust system in
my 1978 L48 to true duels and headers. I have read some of the
other postings about the different brand headers and systems but
my concern is ground clearance. Where I live I need every bit of
clearance possible. Can anybody tell me which headers would be
my best bet? Has anybody ever used Hooker duel exhaust kits?
Was there a great deal of power increase after the change over?
What about a balance pipe between the two banks how necessary
is that? Any info would be greatly appreciated. thanks