Cfast
Bosch 300's and 275's are the same injector, they are good for + 40 HP or so.
Mach 2's are +105HP
Do some searches there is a bunch of info. out here.
I had 275's for less than a year before I bought the Mach 1. 5's. I new right after I put in the 275's I wanted more. So in my case they weren't a good deal, just an extra expense.