Hope I can explain that to all.

No need to make extra caps. Only take off that belt and the pulleys. Let them be there, no harm. Just a little bit safer engine.
No horsepower on my mind, when we take that belt off.

When you put that 1" belt the distance between cam pulleys and beltwheel? ( that part which is lowest part in the way of belt) is not the same as original.And I mean the distance between cam pulleys and engine. So you have only 2-3 mm distance between 1" belt and balancer shaft pulley.(the first one, when you look your engine forward). Manufacturer recommended that, that pulley will be taken off. It is hard to explain and I don`t have any pictures. Sorry.
This set costs little bit over 400 € and it is full set. The belt is from fiat ducato 1.9 diesel engine. I don?t know where the beltwheel? is from, but it?s ordered from factory of fiat, so it will be genuine original part also. The rest are custom made parts. Manufacturer of this set recommended that same 60 000 km as Alfa Romeo, but as you all know that 60 tkm is a little bit too much for that original belt.
When I get my engine and clutch ready I will make some test drives and tell you better feelings of the car. Hope I get also few extra horsepowers also