please stop calling them 4.11's...our axles have an available 4.10 ratio, no 4.11's.
secondly, so called "cold air intakes" arent going to improve anything unless you happen to be carrying several hundred dollars in pennies around in the back of your truck which you consiquently spend on your shiney intake system. the factory intake is already a true cold air system, which is more than sufficient for a stock engine, and also includes a preheater to get the engine up to temp. faster on cold days...thus improving cold weather driveability and fuel economy. most "cold air intakes" include an exposed cone-style filter element which sits in the hot engine compartment and breathes hot engine compartment air...making it a warm air intake which is more likely to decrease fuel economy and power.
and dont get me started on aftermarket exhaust systems....
this has all been covered a thosuand times before. if you would kindly refer to the "search" feature at the top of the page.