changing air filter and muffler

Just got a 2012 winnebago on a E450 chassis with the V10. Runs ok but has anyone installed a free flow air filter and or exhaust (cat back)? If ya did what results did you see? I have written to hypertech about a tuner but they do not have them for the v10 in vans:(

Also what kind of throttle control do you have, this one is not real responsive once under way unless you push to passing gear. Nothing really between what is there and the pass gear downshift.

If you run a tuner which one, how effective is it?

thanks Hank

Looks like few if any add performance enhancers to their rigs by lack of response. But just to let ya know I have correspondence from a place called 5Star and they do tuning for the vehicles. Have several different tunes to add and there is some indication mileage may improve some. Anyhow just wanted to let ya know, I will be trying their product as soon as I get some extra $$, it cant hurt.