Sounds about right.
Not sure if the 3.2 is harder to fit but the 3.0 is an easy swap so if the 3.2 is any hassle at all I'd sacrifice 7 bhp for a much easier transplant personally.
This was the advice I got:
3.2 is a better engine main advantage is it has a steel crankshaft which is lighter and stronger.
The vectra 3.2 is probably the best engine to carry out a conversion with for the following reasons:
it was the last engine built so has all the engine mods i.e latest hydraulic tappets, oil pump, block design, also has the metal sandwich type head gaskets fitted - these are the type they eventually fitted to the rover to solve the head gasket problems they had.
it was also the only v6 built that used fully synthetic oil