Thermoquad vs square bore
OH, I also want to add, though I've never own a Action plus, being a dual plane intake of a high rise fashion, it should do very well comparably next to a modified LD340. The LD-340 is no longer made and found cheap by compare. Modiefying it to work with a T-Q is easy. But if you didn't have tools to do it and just wanted a OOTB intake that will do well, if not as exactly well, get the Action plus. I don't see a single reason why it wouldn't perform well.