I got a 99' high compression JDM b20B with one of those wierd box style intake manifolds on it. I cant use it though because it wont fit under the hood. I compared the b20b IM to my stock B18A IM and the ports are way bigger on the B20 one so I dont want to use my B18A IM because it will hurt performance.

What would be the best choice for a intake manifold on a high compression B20B in a 90' integra GS. the car is strictly a daily driver and all I have is a megan header, aem short ram, 2.5" exhaust going to a fartcan. So the motor wont be heavily modified, I just want it to run to its full potential and using the smaller B18A IM wont be doing that. So what IM should I use to get the most out of my motor? Aftermarket or OEM?