I did have issues with the Singer at first but it was mainly my fault. I bought the alternator from someone with a 2.2 cobalt. I contacted Mike Singer and hooked me up with the external regulator for the alero. I didn't install it so I sent it to him and he fixed it and upgraded parts for free. The warranty was transferrable, I only had to pay shipping one way.
2002 Alero GL 2.2L Eco-tec w/ 87,800km
New System in Progress...Mids/Tweets: 2 Skar SPX component sets powered by a Skar 85.4. Subs: Hybrid 15" DD/AA, Amp: Skar SK3500, 2 runs (power and ground) of Knu OFC 0 gauge, XS d3400 up front, 2 Deka g31s in the trunk...more to come