something that has not been mentoned here or you might have found out with the HVH SUPESUCKER spacer and like brands..is that its
much more than just a spacer..the bottom side has a unique patent design that has engineered peaks and SWIRLS design specifically to direct the air/ fuel into the motor for Optimal peformance..(much of the same rhyme and reason a good intake man will work an intake)......this is wy they are so high ($$$) BUT WORK SO WELL..these results are dyno proven tome and time again..on my 511ci you could tell the differenc ein the throttle reponse and ET.
if not for all this engineering with hours of R/D...There would be NO differance than running a cheap $20.00 Mr gasket 2 inch spacer.....
so there is a reason why these type of spacer plates work above and beyond ( and cost $$) your run of the mill spacer plate.