05 4" kit with split duals

[kevinmach1]

Chris, I just installed the magnaflow 4" kit with split duals and 5" tips on my 05 6.0 SD. It went pretty well installation wise, but I have a question and a suggestion.
1st question, At idle, I get a strange rushing air sound from the exhaust tips which almost sounds like a big vacuum leak (not a whistle sound), any idea what is causing that?
1st suggestion, to help get the 4" downpipe installed, have the installer remove the front cab bolt on the passenger side a slightly either jack or pry up the cab to allow enough room between the firewall and the engine to get the pipe snaked in. That would have saved us alot of time and fustration installing the system.
Other than a few little tweaks, it went on pretty nice and sounds nice and quiet with a aggresive note on hard throttle.
Thanks...Kevin