erk... i never tested with other ppl on the road. i dunno what chip is it, my mech did it for me and he didn'e mentioned anything about it. originally was DA8 automatic ecu rechipped for manual use.
anyway, what's so strange about it?
too fat i think... will produce low velocity in piping... bad for engine power... if the car have done extreme internal mod... 2.5" matching kot... but the biggest i've ever heard was 3.0"... the eg using 2.2 litre block... only half piping...
my frens always use small piping such as 2.0" for stock b16a... eventhough the engine have done lite mod n port polish... to me it's small... but they don't agree... hhehehe...