i just went to the RB forum & did a quick search on the words "Ofna pipe"
[link=http://rbproducts.com/rbww/ubb/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=001329#000000]HERE[/link] is just 1 out of about 20 results on this topic
i have slso read a more detailed analysis on this difference in materials but cannot remember where i saw it

it was possibly on the Serpent Forums at
www.mytsn.com
now those on road 1/8 boys know everything there is to know about going Very fast