your set up you could have about 700 or 800hp with a twin turbo set up on 92 octane and run it every day without a problem but like i said it needs to be set up right and grant it that there is more to setting up a twin turbo than a blower

the engine needs to have a max of 9 to 1 compression
you need an intercooler
and you need to have an oil cooling system


this is my opinion i think that a twin set up is way more impressive than a blower (no offence) because there is more to it than bolting on an accessory

also have you ever seen a belt fall off of a turbo?
more components but less to go wrong
because if your blowoff fails the rubber fittings in between the connecting tubes its a fail safe system and if yur fittings do come appart you still can drive it home or simpally fix the problem on site