Extension Cable

I need some extension cable and I was wondering whether a 6 meter cable would have significant losses compared to a 3 meter.

The 6 meter will allow me some flexibility on more access points but I'm not sure it will be worth the signal loss.

I am using a Belkin card w/ a 7dB gain antenna.

This is the cable I was looking at, is it good quality:

eBay: Antenna Cable SMA male to RP-SMA m 6M wireless pigtail (item 5866123199 end time Mar-08-07 19:51:56 PST)

I was also looking at this:

eBay: 10' Hawking, DLink, D-Link Antenna Extension Cable SALE (item 120088345468 end time Feb-24-07 08:42:40 PST)

Which one is better quality or does it make a difference?

Thanks

Anybody?