hey mate. they look the same size to me... i had a e business supply 49cc dirt bike and they look the same, minus the side part of the frame. To me it seems the bike(s) will go the same speed and be close to same quality. Keep your bike and add some go fast goodies to it. Check out
Ozminimoto - Mini Pocket Bikes - home and go to spare parts. Have a browse at the gear they have, then do a search on here for 'spark plug' 'fibreglass reeds' 'headkit' '14/14 rep carby' etc and have a good read of all the topics. Everything has been covered for you over and over again, so it's easy