radardoug said:
I use Thiersch in Switzerland.
Didn't know he has moved to Switzerland... ;D
Adress:
Thiersch elektroakustik
Am Dorfplatz 22
07907 Schleiz OT Möschlitz
Germany
The K103 is by no means a single - sided K87 knock off. This is one of internet legends... unfortunately Neumann has caused it to some extend due to marketing bs.
Everyone who has seen the two (original) capsules side by side can easily spot that the most common part is that the capsule is made out of brass and has holes in it. As soon as it comes to the hole pattern itself it starts to differ... they even don't sound the same on axis.
You first should ask yourself if you like the TLM103 as it is.
Putting another capsule in there will change the characteristics of this Mic dramatically.
No one will tell you something like off-axis behavior of a different capsule in your mic.
In the end this will be just trial and error.
You'll certainly won't make the TLM103 'better' just different or even downgrade it.
The best thing for your TLM103 certainly is to get the original capsule reskinned by qualified people (Thiersch is a good recommendation).