Starter prob

Hello everyone I am new ofcoarse........have a prob and thought someone could help me out........just bought a 91 TSI FWD supposedly the car runs.........put a new battery in it........tryed to start it and it just sat there and wouldnt even turn over.......took starter off and had it tested and it and solenoid were both good.....when I have the headlights on and try to start the car it turns headlights completely off....until I let off key could this indicate wiring probs maybe ? also it has a greddy boost controller on it ..........whats max psi ran on these things?......im a first time owner of a turbo car.........noob as you could call it lol any info would greatly be appreciated thanks