An upgraded alt is always a great idea - the bigger the better. I have a 200 amp alternator in my 67 mustang, alongside a yellow top battery, and I still get the slightest bit of dimming when the bass is pounding. Which is a lot better than having my HU flash in tune to the music if I run the car of a charger Same goes for the big three wiring upgrades - just make sure that you get a very clean ground connection from the battery, sand off some paint on the chassis if you have to. As far as sound deadening goes, I would recommend Ant's products over at secondskinaudio.com - I covered the firewall, the inside of the doors, the entire floor and the space behind the back seat leading into the trunk with his stuff & noticed a huge decrease in noise. Next up is the headliner which'll receive a couple of layers too. He also hands out a mighty 40% discount for people who hang out on the caraudio.com or caraudioforum.com forums which rocks. And, yeah, a heat gun (or hair dryer) is a great tool to have around when applying dampening materials. Lastly ... I've said this before - I'll say it again: the SI components are sweeeeett, and make a fine pairing with the magnums.