I have an ASP Underdrive for my VE and haven't noticed any difference in my air conditioning or alternator power, the blehmco ground kit may have helped with the lights dimming issue when you're in park and try to roll up all four windows at the same time and stuff, but it was negligible; I hear improvements are more noticeable on a 5-speed, I'll let you know in a few months
About your question, Air tools are definitely recommended, I wouldn't even want to get that bolt off with hand tools, ugh. But I'm sure it can be done with a breaker bar or something, just be sure it's on good and don't round it off.