you can get the same style of injector with higher flow (I think 200cc/min may be a bit low for higher horsepower). The newer injectors are usually hi impedance (z), your megasquirt can handle both, the L-Jet can also handle hi Z, I have been running hi Z 220cc/min for years without any issues. The only issue is that some ECU's can only handle hi Z then you CANNOT use low impedance injectors alone (you need to use a pull up resistor). if you use this calculator it will give you an idea on what flow rate you need for the amount of horsepower you are designing
http://fuelinjectorclinic.com/hp-calculator duty cycle should be 80% for normal conditions, (you don't want to drive your injectors too hard) (the calculator recommend 90% I personally think this is a little high, I think it is better have a bigger buffer just in case you have to push them harder??)
as a guide this ebay link
http://www.ebay.com.au/itm/VL-TURBO-INJ ... tTycNSMqdA (no relation to it) has 250cc/mm and are used in a 6cyll turbo motor from the late 80's, the changes may be the hose length and sometimes the o-rings are different sizes.
If you want to use modern injector then you will have to fabricate a fuel rail and regulator to suit (and maybe change the connectors), the challenge with our cars (from memory) is that the all 4 injector don't come out parallel with the standard FI system, making it difficult to adapt a straight fuel rail.
If you are using throttle bodies different story altogether