I had done a bit of reading before i decided to buy the MCAI and have a crack at the 2 hole mod. Thought i would just post some interesting findings that i was unaware of... or that i had been too ignorant to notice...

1. The airbox in my SS already had 2 holes in it. One snorkel to next to the radiator and the other down behind the front end.

2. The original holes in mine were 90mm and around 50-60mm(didnt measure the smaller hole).

3. After cutting the second hole into the MCAI shroud (90mm), i had to then expand the hole in my air box. With the original airbox there was no way a 105mm and 90mm hole would co-exist, therefore i ended up with 2 90mm holes in my airbox and a 105mm and 90mm in the shroud.

4. Had to then use not one but two pieces of 90mm pvc pipe for the shroud and thickened up the middle of the pvc pipe going to the 105mm hole in the shroud and siliconed it so there wsa no gaps.

So after alot of mucking around it was done and im extremely happy with the results especially after getting a k & n filter. -best 30 bucks ive spent on my car...

to all those out there that had the same questions as me hope this helps.
happy tinkering.