i think it maybe not la.........too strange......and also affect the performance la......
for your 2nd question,
in my own opinion......maybe related to the history and performance issue....
the old GP is bit bigger than EP to get more room for engine and electronic stuffs.....so the GP today also use the same scale.....keep it big....
the other reason maybe (just guess!!!) related to power and performance.......GP have more power output...the car have to be more stable to keep the good performance....wider body can make it....
EP have relatively lower power......shorter in width may make the car move better....cornering sharper........all my guess.....any brother have the true answer...please call!!!!