Allmachtige is right, '95 was a transition year. Yours has 225hp. In '96 they had 240hp and in '93 they had something around 205hp.
The SC engine in '95 was the series 1 and the NA engine was the series 2.
Boost. Not sure what the official rating is but I get up to somewhere around 7-8 psi according to my gauge. I think the M62 was used from '92 - '95. Not sure what was used before then.
Not sure of your knowledge on superchargers vs turbos so forgive me if I go too simplistic. The supercharger is run off the main belt. If the pressure reaches too high of a point there is a relief valve that opens and dumps the air out instead of blowing up the unit. The guts are two rotating gears that trap the air between them as oppesed to the turbo which I think uses a centrifugal fan type setup. This is a general supercharger statement I am unsure about our model specifically.
If you are going to add a smaller pulley I would defenitly do the following first ( not in any perticular order):
1) Cold air intake
2) High flow exhaust
3) 180 therostat (195 is stock)
4) Transmision cooler
1) Better plugs (NGK)
2) Better wires (Taylor or MSD)
Just get it breathing really well before you add a smaller pulley otherwise it won't be fully utilized.
One more side note. The '95 SSEi was (from what I've heard) the lightest year for this car of that body style ('92 - '99), wieghing in somewhere around 3500lbs.
Hope some of this helps.