As usual, I totally agree with you. I didn't want to go into any specific test designs in this thread as it is well beyond the scope of what was being asked. However, if I could find a local PC member I would be happy to lend them my 15's that are broken in and RPM can be estimated. I find it interesting that no serious testing has been done other than the UK test which found there was only a 1mpg difference. I trust that study as much as I trust Al-Qaeda!
