For all you guys going big hp and are looking for a 90mm maf housings. I have done some searching and found that the B5 RS4 (2.7tt) uses the same part number as the B7 S4 (4.2 V8)
Part number 0280218067 - 90mm maf with sensor
Bosch Automotive Aftermarket - Products
Got this off a B7 S4 for $50 shipped incl sensor, not that I need it - there are a few guys on Vortex parting out S4's - gets yours while they hot
Part number 0280218067 - 90mm maf with sensor
Bosch Automotive Aftermarket - Products
Got this off a B7 S4 for $50 shipped incl sensor, not that I need it - there are a few guys on Vortex parting out S4's - gets yours while they hot