Belt Rubbing in 4 different spots, am i loosing boost?

well, i knew after the first day my friend finished putting the s/c on my car that the belt was hanging half off the idler pulleys. well after my dyno, i have decided to fix the problem. since i am a full time college student/baseball player/ Radioshack employee, i only have the early morning hours on saturdays to work on my car (9:00-12:00). anyway, i pulled the head unit off, and noticed that the idler pulley left of the unit, closest to the fenderwell, was so loose that it was about to fall off and was on bassackwards:mad: and that he also had the two idler pulleys in the opposite places. well i've got that fixed, and all i have to do is just bolt the head unit back on, bla bla bla.......
my question is have i been loosing boost, i noticed the belt was rubbing in like 3 or 4 spots? do you guys think this should fix the problem?
thanks

If the pulley was assbackwards and you put it on correctly, then that should fix your rubbing problem, unless your having alignment issues.