Upgrading to 180A alternator

[Lapik]

Has anyone attempted an successfully upgraded existing 120A alternator with 180A unit from B6 Passats on Mk2 Sharalhaxys? I am planning on fitting additional electric heaters to aid heat input to cabin heater - here in Estonia, it goes to the other side of -30 degrees in February and my dear Tdi Galaxy fails to produce enough heat in this case to even get the engine to +50 degrees, let alone cabin heater. Aux heater has already left my car before arrival to my hands and I'm not very keen on spending some 700'sh on reconditioned unit. I will be looking for a reliable solution but until then I'd like to add some extra heat to coolant by using a coolant heater from my old Berlingo. It uses 4 glow plugs to heat coolant- very quick and compact solution with furious current draw (ca 90 A at full power), which led me thinking on upgrading the original 120A alternator (which is putting up some bearing noise as well) with more powerful unit. Mountings and connections are similar, I already have a stronger 50mm2 wire prepared to allow higher amperage, but as I don't have my own garage yet (and it's already lots of snow on the ground) I'd like to konow, if it physically fits the engine (the diameter of 180A unit should be few mm bigger, but I haven't got any in hand to compare these sid-by-side.