I'm not sure who you're asking but I'll answer lol. I put in the 220 amp alt before I even hooked up my stereo so I can't answer about the subs cutting off in the Blazer. When I had the same stereo in my Mustang with the stock alternator the engine actually quit running when I cranked it way up at night with the headlights on lol. The volt meter dropped down to 8 then the engine cut off lol. But the amp still played . It's not good for electronics/sensors etc. to drop down that low. I know the stereo I've got can suck some serious juice so I just put a better alt and battery and upgraded all the wires before I put the stereo in. I don't have an Optima- I personally have not had good luck with them. I've had yellow tops and the longest one lasted me 4 years. I don't sit and listen to the stereo with the engine off for extended periods of time so I didn't think I needed it- that and the warranty kind of sucks, they're not pro rated, and I could get one with higher CCA's at Autozone so that's what I went with. It's pro-rated for I think 7 years and has dual terminals so I've got an extra ground for the battery and just use the top positive terminal for the stereo. I'm not sure what everybody else did but I pulled up the carpet in the back where the box is and took a chisel and got rid of whatever rubber coating was on the body; sanded it good with sandpaper and grounded it right there. Each amp has it's own ground and I did use 0 gauge for the grounds. Can't have too big or short of a ground. I haven't had any problems with it and don't get any feedback noise.