computer tune and lube reviews and complaints

So I brought my 04 BMW there back in June for the emmissions testing and it had not passed. They did a diagnosis and gave me the result. The manager "josh" made me aware that the O2 sensors were the cause and that they needed to be replaced. I asked what was causing them to go off and was told it was running to lean. Then he gives me the estimate... 950.00 bucks! No was I paying this and no way the parts would even cost close to what they wanted. Ok.. so i have a friend of mine that knows everything there is about cars and he takes a few things apart to look around. See's that there is this rubber boot that connects the air intake ( a rip will cause the car's O2 sensors to go off thus making your engine light go off. Brought the part to west springfield BMW... new part cost... 16.00! Got it installed... had all the engine codes rechecked and had my car retested somewhere else... PASS! So lets get this right... first computer tune and lube mis-diagnose my car... then they want to charge me 950.00 bucks. Granted I was never going to pay that because the true problem never would have been fixed. Do yourselves a favor and stay away from them... unless you don't carre about being ripped off. That place should be closed down period!