nope.. you still have the speedo percentage of error to have in count.. if its arround 8-10% at 250km/h or 160mph... the real velocity will be 225-230km/h or 141-144mph
.. but ive seen it.. on a straight road.. tecnomap program, a tube to eleminate cat, BMC filter, polished admission.. and 250-255km/h
But i still dont understand, why do you think that thats so hard?
I had a Renault Megane 2.0 150hp no tunning made, and on a straight road long enough (not a 10mile road
it would reach 238-240, and then the ignition would cut the gasoline..
Ive got some curious fotos for you then.. a Civic Type-R with modifyed exaust, and filter passing the 260km/h mark going on a straight road and a reprogramed audi 130tdi guiving arround 250 on the climatronic(pointer260)going downhill
.. but thats on the velocimeter.. obvious youll have to discount the vm error percentage: