The difference is a V3 has a close decked block? and revs to 8250 rpm,the V2 7500 rpm.
The V3 has red cloth seats and a carbon look dash!
My version 2 made on 5/96 did have 2 pots and i think the 3 has them too?
Mine has a water intercooler spray fitted,its an option with that or ABS.
The same on the 3
They have the same performance and most of the other charicteristics are the same
Hope this helps
Darren

 

What are the main differences between an STi 2 and an STi 3 ?

Also, were all STI's made with 4 pot brakes or did some of the earlier ones have 2 pots ?

 

The three has the facelift grill.

 

from - 'official impreza history'...

main points in favour of the ver 3
were more power and torque (only 5 more bhp but a useful hike in torque)
stronger pistons and cylinder head bolts
4 pot brakes
revised front grille and bonnet vents
stronger crossmembers and more rigid body
nicer seats/interior

though a ver 2 with added 4 pots and a new front end is arguably not much different.

fwiw

Paul W