one thing you have to take in mind is the b20 sleeves are notoriously weak, they crack with to much boost pressure or around 12:1 static compression ratio.
If you really want to go with a b20 I suggest sleeving it before you do decide all motor or turbo.
I made 300whp and 298 wheel torque on my bone stock b20b motor with a pieced turbo kit. Not weak unless you dont tune and beat the hell out of it. Oh yeah lasted 2 years and then I just built another motor the b20 still ran.
I had my all motor car for years before it blew. It was a blast to drive. Ill be able to farther compare the two whenever my turbo setup is done but Im willing to bet I love my turbo setup alot more than my old all motor