i run the V1 SC trim blower. it made 5 psi out of the box on my engine ( thumpers, typhoon and b-cam) but i ran it at 9 psi for a while
i have since gone to an f-cam and got bigger valve put in my thumpers.
i ran 19s with the FMU making 9 psi, it ran alright. but it being untuned... blew a HG at the track. no wideband or anything i was in the dark.
i also ran the car with 42s (untuned and NO FMU) and it ran and drove ok but seemed to run rich and i lost alot of power. i mean a huge loss of power. the car ran better at 5 psi with the FMU than it did running 9 psi with 42s with no tune.
got my car back together with the new goodies and am running the 42s with no FMU ( i plan to tune it with a tweecer) and it runs pretty bad, it will run and drive but it just isnt right. it acts rich but my WB shows dead lean so i may be burning excess fuel in the headers i duno.
but getting the car tuned will cure all that. with a good tune with 42s the car should drive and start like a new car and the AFR should be dead on at WOT etc etc. and should pick up some power.
i WOULD NOT run the stock 19s with no FMU, the stock injectors alone will not be able to feed your combo with the blower and you could detroy your engine.
i also wouldnt reccomend running the 42s with no tune, it will run worse. but get it tuned and it should run great. and you cant really "oversize" an injector. with a proper tune you can make 42s work perfect for even a bone stock engine that will never use that amount of fuel. 42s with a mild HCI and blower is just about right. 42s will MOVE ALOT OF FUEL. if you plan on keeping it mild and not upgrading boost you can probably use 36s and be fine. but a bigger injector will give you some growing room if you ever decide to upgrade power/boost
i could see running HUGE injectors like 150lbers could be overkill. you would be running such low pulse widths it would really narrow down you tuning range and make it harder to tune if you get what i mean.