thats how i've got mine, and i'm not sure on any gains yet, when i first put it on i checked it and the filter seemed maybe abit hot, but last week or so it has seemed pretty decent temperate
boost creep seems to be a little less, also, the filter may have the fan blowing on it, but at same time, with the original pipe, was in exactly the same place, plus being longer it would get more heat soak, surely?