any modded car is going to have problems if the maint is not kept up....
as ive said before, reliablilty comes from the tune, not the parts/setup. You could have a turbo setup that is 10 times more reliable than an untuned nitrous/allmotor setup or just the complete opposite.
An off the shelf nitrous kit is going to have a smaller upfront cost compared to a turbo setup, but in the long run it could cost you lots more (ex supporting mods, bottle heater, refilling, refilling, and refilling the bottle etc etc)
Figure out your budget and then decide what kind of power you want and other goals such as what kind of 1/4 mile you want to run.
Example being me:
I have a 90 civic si with a b16 cable lsd tranny. I want 250-275 on my stock b16 and hit high 12's on drag radials. Im going to do this by putting together a turbo kit myself, installing it myself and basically doing everything but the tune myself. I have a budget of 1500-2000 that i will not even come close to topping out (hopefully lol). So far i only have a few parts but ive been shopping for the best deals and should have it all together to install by the end of may.
That is my goal and that is what im going to do, try to go about it the same way. Write out your goals and then see what its going to take to get you there, and how much its going to cost