2009 Focus 1.6tdci engine tick

Hi all I have a 2009 focus 1.6tdci with 125k on the clock, my friend also has the same year focus but his is much quieter his has 138k both have fulL service history.. Could it just be my injectors rattling or does it sound more terminal?

My car runs fine but there is a distinctive noise difference between the 2 of them as per the clip. The is a difference as you will see on the left hand side of the engine (Drivers side)and the DPF is different mine has the eolys system his doesn’t. 
 

The reason for my question is firstly why does mine tick like that and why the difference in engine note (I appreciate every engine doesn’t sound the same but this is in my opinion quite a change) and secondly as his car has just being written off due to a rear end shunt is it worth doing an engine swap? And can that be done given the difference to the pipe work etc on the left hand side and electrics/ wiring look? if these parts are not compatable can they be swapped over to match the wiring loom as the engine numbers appear to be the same?

my engine 

other engine 

 can’t see how to add a audio file? So I can show you the ticking I’m talking about and the difference in engine noise?

any help would be appreciated 

John