I think it depends on the engine really, you need SOME back pressure in any NA car because when the fast moving exhaust gases are expelled from the piston and into the exhaust manifold, they create a low pressure area behind the fast moving gas which ideally should suck in fresh air/fuel through the intake port. This is why NA engines have valve overlap, to promote more sucking action in the piston chamber (when the intake and exhaust valve are both open at the same time)

How much back pressure and how little I don't know for honda engines. I would guess that you want just enough to suck in air, but not enough pressure to pull air in through the exhaust port.