I really dont think that inj. is harder on an engine than anything else, i think that deal comes from people that are wrench happy with their barrel valve, then they get the whole milking thing going on, or they wash down cylinders among other things ,,and i understand there is a fine line from having a crisp response to off idle stumble, usually people fatten the barrel valve too much in most cases, if you have it set up right then you are fine, but it does take effort and in some setups espically if you have the wrong size fuel pump or nizzles or other things it can take quite a bit of effort, some get frustrated and say the hell with it, but once it is right they work great,but i have seen some nice engines die a miserable death due to people not having a clue ( or would not listen) with injection,,,
Years ago when the toilets came out i got one and picked up 4 tenths --hell i was sold , who would not be, but at that time you could not pick up the phone and order a custom carb, you had to buy one out of the box and screw with it for a couple of weekends to get it to work decent,,,,,
fast fwd to today, carbs have come a long way in the last few years they do not requier near the signal to operate they used too and you can pick up the phone and have a custom carb built for your combination that is usually close to spot on when you get it,,,for years i would not even discuss a carb let alone purchase one i was an inj diehard till a friend finally talked me into trying one , ran it for a season and sold every inj piece that i had in my shop,,,but that is just me, usually when you get into the carb vs inj debate it starts a world of shit and is not my intention here what so ever,, both work good and whatever route you chose people will be glad to help you with either one here,,,i just would like to point out that if your carb was right and tuned for your combo then dont expect 40 hp gain, what you will see with inj is the response different than with a carb and you can get up on the chip quicker , some cases you will pick up in the 60' and sometimes you may not, every combination is different, when i switched to the carb my 60' actually stayed the same but i picked up a couple of hundredths on the big end and a little bit over one MPH, you may or may not,, but i hope you do