Q1 - You won't notice better MPG,s but the rover will love you!
Q2 - Yup, they get warm.. just watch the guage as to not overheat!
Q3 - The K&N really seem to cause a lot of issues with the MAF sensor, with the price of those you don't really want to mess with them!
Q4 - Well the rover is nothing like BMW for highway speeds and such. I have a dead area from 65 - 75 (or so)
Q5 -
Q6 - Personally I like the Rovertym bumpers(
www.rovertym.com) but other companies such as TJM, ARB, Equipe!