If you have a stop bypass valve (BOV) the rattling sound could be it fluttering. Depends on what it sound like.
As to hesitation between shifts, a turbo with a stick takes some finess to drive well. Being able to slip shifts fairly briskly will reduce the lag that you get with a slow shift. When you close the throttle body the bypass valve releases excess boost that would slam against the butterfly valve. That is good for the throttle body but not good for keeping boost level up. Turbos work well with automatics for just that reason, you can just keep your foot in the throttle. I just like to shift myself though.
Spooling up? If you have an some type of open intake like a Airraid or the like, you will hear a pronounces whine as RPM's build, mostly under WOT above 3000-3500 RPMs. Sounds like a jet engine spooling up only not so much so.
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 '03 Inferno Red GT, 5 speed, STAGE 1, Mopar BOV, Plastic Intake, Modified Upper and Lower Airbox, Custom Airbox-to-turbo pipe, Borla dual exhaust, Maddog Short Shifter, Drilled/Slotter Rotors, Ceramic Pads, chrome wheels, chrome door spears, AMP chrome fuel door, PT Cruiser 3rd light diffuser, H&R Springs, Rear Sway Bar added, MGW chrome door lock pulls, Blane's hood struts, Custom license plate mount, some interior dress up stuff...more to come
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