2006 bmw, stereo

[car = 2006 BMW with Harman Kardon "premium" sound (Ha!) driven by small factory amp]

1- do I need to run new wiring to my front speakers (6.5") or can I use the factory wiring coming from the old factory amp.  my new amp will deliver ~40W/ch.  Realistically speaking...

2- what would you recommend...I want to incorporate some quick connectors so if I need to remove sub/amp box, I can click and pull.  There would be (2) connector sets, 4-pin each, from the crossovers (also mounted on sub/amp box) leading out to the front speaker wires.  Don't have to be pretty or necessarily bullet-proof.  Any suggestions?

Thanks!

Ref question #2...

Anyone have any ideas for the connectors?  Should I just go to radio shack and see what's available or are there certain quality issues I have to take into consideration?

In other words, I could go buy trailer wiring connectors, but would they be good enough quality or would they be bad for transferring audio signals?  I don't want to degrade the signal by going "cheap" or cheezy...

Almost to the point in the installation, so any replies would be appreciated!

Disregard last post.

Thanks.