Mark, Just got it in mail today,but it is larger in OS diameter than mine, so will not go in my dash opening.
Is the boomerang out of a sky? Mine is a GXP.
Yours 2 7/8 dia
Mine 2 1/2 dia
That's very strange! No, it's out of a Solstice (Sky vents are rectangular). I compared the front of the remaining one in the boomerang, with all the ones in my GXP (an '08) and they are all the exact same diameter. So I don't understand. What year is your car?
You ARE measuring the plastic tube, right? Not the foam seal?
I just checked the Nalley site, and it shows the same part for all years:
003 15824746 OUTLET. Air Distributor
OUTLET,I/P CTR & OTR AIR(EBONY). Required: 02
For: M (2006-2010) (2006 - 2010).
I'm guessing you may just be having trouble with the foam seal (I know, it took me a LONG time and a lot of squeezing to get it out). If that's the case, your best bet may be to take the foam strip off, insert the tube, and then reattach some foam weatherseal in it's place from the rear.