i plan to do the RU-2820 conversion in my type R, but i think the K&N's diameter is too small! its only 3" while the base of the OEM R filter is 3.25... is the GSR intake smaller than the Type R?

 

The ITR piping is larger.

 

Why don't you get the direct replacement filter...? E-2427...No hacking the stock filter to pieces!

 

cuz it doesnt seal up as well... plus i need an excuse not to do homework

 

Don't know what intake you're running...but on my Icebox, the elbow on E-2427 fits 10x better than the stock elbow ever did.

 

how big is the opening of the E-2427?

 

it's a drop in replacement filter... how could it NOT fit?

 

All G3 Integra use the same filter. The filter opening that fits inside the rubber intake tube is 3.25". But the opening on the stock filter that the K&N fits onto is 3.125". The RU-2820 flange opening is 3.0", so the flange will need to be "stretched" to fit on the stock filter elbow. But with a little patience the RU-2820 will fit. HTH