just a few concerned questions

i just bought a very well maintained laser rs turbo awd... it has a exhast leak right befor the cat and muffler i noticed it doesnt have very much boost its pegged at -7 vac till i really get on it kinda hard. then it slowly builds to +7 boost now is that because of the exhaust or could it be some thing else and also extremely hard to move the shitfer into any gear especialy into 3rd what could cause that

thx appreciate it