I done my install this weekend, to keep any possible restrictions down this is what I used. 2 ea 2.75 ID semi-truck radiator hose's 40mm long & 2 ea 2.5 semi-truck radiator hose's just wide enough to fit the notch of the OEM air boxes. I also used 2-3/4 piece's of exhaust pipe inside the 2.75 hose's to keep them from collapsing when inserting them into the SL55 hose's. Since the SL55 hose's are oval the round hose's I was using did not want to fit correctly, so after getting them in the best I could I used a little hand held bar clamp to reshape them to the oval position. Then the 2.75 hose fit like a glove, I then put the hose clamps on & tightened them down snug. After that I used the clamp to make them round again. I ended up having to trim a little off the corner of the lower portion of the air box, it already had a notch there. I tried to do the install with one air box left on the car, installing the "Y" then the second air box, but the smaller hose's I'd put on the air boxes kept slipping out of the big hose's. Soooo, after getting things together the best I could on the car I pulled both air boxes with the "Y" & hose's all clamped together. I sat the whole thing on the bench to make adjustments and make sure the small peice's of hose's were in place good. I then tried to mount it back on the car but the big hose's were hitting the supercharger screw covers. So I pulled the whole thing back off and used the bar clamp to bend the large hose's that have the peice's of exhaust pipe in them for reinforcement to an oval shape. The gains I got on a G-Tech meter were .162 @ 3.16 mph in the 1/8th & .362 @ 3.76 mph in the 1/4, 0 to 60 4.316 to 4.110. The G-Tech will give you a HP & TQ readings also, it showed a gain of 27 hp & 19 tq from my best previous run, but these gain also include removing the resonator.