Motor and Battery question

OK, seen as though you're all so very helpfull - next question.

I read somewhere on here (I think) about a esc mod (resistor? - maybe while searching specifically for quark?) to reduce/stop arcing when connecting a pack. Well today I put the 5.5mm bullets on esc and motor and when I connected it up for the photo's (see buggy thread) I got an arc. I never had this before when I used 4mm. I understand the bigger connectors will allow more current/voltage/power through but is it really this big of a difference?

Tomorrow is the final test day before I fly out to work again so I'll be sure to post my latest speed figures. I'm positive it's going to need gearing down before it hits the track.

Cheers again,
Clip