thats not the only difference. the u87 uses the
K67capsule.. The TLM 170, TLM 193 and
U 89 all use the same capsule, the
K 89.
the U87 is rumoured to be "brighter", supposed to have more detail and was designed to be more up front sounding(in its cardioid setting), where the U89 is almost neutral, very flat...
u87s are a legend in their own right..by the 1970s it was "the" mic for professional studio recording. A lot of people still use it as a go to mic for vocals. Stephen Paul Audio worked out a mod for the u87(focusing on diaphragm switching) that is pretty popular in high end studios. Klaus Heyne also has a mod for it(u87) that focuses more on the electronics of the mic...
I have u87s and like them a lot more than the u89s I had. YMMV