Ok... I was also looking at the KN RC-4630
K&N RC-4630 (RU-3530)
Mounting Dia = 3 1/2" (3 3/4")
Filter Base = 5 1/2" (5 3/8")
Filter Top = 4 1/2" (4 3/8")
Filter Length = 6 1/2" (7")
Flange = 1 1/4" (5/8")
Compared to the RU-3530, its got a 1/8" wider base, 1/8" wider top, and overall length (Filter + Flange) is 1/8" longer... Although I'm not sure if the extra 5/8" flange is buying enough room for the IAT. It will be more expensive though, because of the chrome ($8.20 more @ ajusa.com).
2003 Focus SVT, Black w/ European Package
26000 miles (Totalled)
1999 Contour SE Sport, Silver, V6 ATX
140,000 miles and counting
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