Yeah, I just bought four of them! 

Bob Hunt

Better yet what do you want to put it in?

For the SV11 4 cell setup-  http://www.innov8tivedesigns.com/product_info.php?cPath=21_120_122&products_id=840&osCsid=43161239709c9e3b48abf0086923a10e    or this one  http://www.innov8tivedesigns.com/product_info.php?cPath=21_120_123&products_id=846&osCsid=43161239709c9e3b48abf0086923a10e

If you want a 5 cell set up let me know

For Vector use the 2820/12  970kv  or the 2820/14 840kv both should be ok on 4 cells

Hey William: 
I would like to know your recommendations for the Cobra 5-cell motor.  Also would there be a significant weight difference in the battery pack needed 4 vs 5 cell ?  Thanks for the help.
 

Allen,
The 2826/12 like Dan says or the 3515/18 should work fine for most of our needs with a 5 cell. For some the 3520/14 may be a better choice. I have no idea what you want to use it in, but those would be your 5 cell choices in the majority of applications. Unless you plan on using those super light Thunderpower 5s2700 mah batteries(10.5 oz I think) your weight for batteries stays about the same weather you use a 4 cell set up or a 5 cell set up. Less cells=lower voltage=higher mah needed.  More cell =higher voltage=lower mah needed. So using very rough imprecise math (I'm no engineer) lets say a 4s4000 weighs 400 grams on average(I know I'm close), I would expect the average 5s 3000-5s 3300 to weigh about the same in most case as long as the C ratings are also comparable. If you go  to Hobby King's website and use their battery heaven battery finder program and plug numbers in for 4 and 5 cell packs using the numbers I just gave you will see that this actually works. Don't forget to sort by weight after you plug the numbers in.

Thanks for the heads up Crist!! 

I have one on order for the Vector that I am building this winter!! You saved me enough to buy a cheapie battery. LOL