the topic has been discussed before. telling someone to study the confuser is pretty crap advice to be frank... any more than 75% will give you better understanding and respect for what your flying so less likley you will end up killing yourself.
study the confuser yes you can pass the exams without having a clue what your doing... good luck with the ATPLs then as you will realy struggle (if you intend to go down that route)
even if you just want to fly for fun on your ppl, when you come across a problem (like the AI failing) you can start trouble shooting and may see that you have a suction pump failure for example..