1987 190e 2.3-16V camshaft timing

[190Blacksmoke]

Ok. I have finally found the problem of the lack of power and quite possibly the terrible fuel mileage. The camshaft timing is off by a decent amount. When I bought the car, the guys mechanic had just installed a new timing chain and said the camshaft timing was fine. But my dad and I just looked at it and noticed the exhaust side was off by 2 teeth and the intake side was off by 1 tooth. So my question is, what is involved in trying to adjust it with the least removal of parts. Any ideas? Would appreciate any help!

Thanks alot!