Can I extend the esc leads that go to the motor ?

[suicideneil]

No reason why you couldnt mount it on its side like that- I think someones BL savage had its MGM esc mounted that wat on a special purpose built plate. Nothing wrong with using the 5.5mm bullets either, but you might prefer the 4mm type as they stay 'springy' for longer. Got a photo of your setup, might help to figure out a new mounting setup for the electronics....