never heard of this css files
use the one that brings a better balance between download and upload
with regards to your tracert there is nothing you can do about it, complain to your isp
say you have packet drops constantly and instead of a tracert ip do a pathping ip
this will show you better packets being dropped and where
if you have a 6Mb download connection u will never get a 16mb download speed
u might be able to increase by 10% or so but not by that much
does comcast have the power boost
if it does you could experience faster speeds due to that