A/C Compressor replacement
 

Not been here for a while but seems i need some help and advice.

I am about to replace a failed A/C Compressor. My car is an early P3 (August 2007) and the part number on the current compressor 8708581 but looking on eBay for a replacement, they don't look the same. Mine has what appears to be a double looking pulley / clutch like this;

https://lh3.googleusercontent.com/pr...zWwhtNUfUHdAdb

Now, can I buy one off eBay with a matching part number and would the pulley / clutch then seperate off my old one or should I look for the identical looking compressor?