thanks for the input guys!

mxwrench,
would it be okay to use a 6mm pipe with a 3port modded engine? (in my case, the OSspeed 12TZ).
or shld i stick with a 5.2mm?
cos you mentioned that 6mm are designed for 5port engines.

i prolly be getting the OS T-1040SC pipe, now deciding btw 5.2 or 6mm.
reason is that i think OS engines will work best with OS pipes.

used to try lots of pipe for my V-Spec (JP2, 063, 086...).
in the end the OS 2060 was the best combo. not to mention that it's the most durable pipe IMO.
(my MBX5 had a side-on impact. pipe bent inwards touching the fuel tank, pipe hanger totally out of shape but not a dent on the OS pipe. even the stinger was perfect! )
only complain was the anal way of attaching the pressure nipple to the pipe itself. why can't they do it just like everyone else?

lastly, juz a side note,
why does ROAR limit it to 5mm pipes? they're pretty rare in my part of the world.
JMRCA has a 5.2mm limit.
what about EFRA/IFMAR?
i think the only valid reason for these restrictions is to reduce power output of the engines.

again, it's been nice chatting wth you guys!