I've seen those leaks at each 'end' of the lower intake where it mates to the block sealed with hi-temp RTV. It'* usually in the 'corners' where it blows out. I personally think this job would be a bit less scary on a SC engine than a NA. I've done it on an L27 for a neighbor, and I've had my SC off, so that'* where my comparison/experience is coming from.
Very few of us here have been that far down into a 3800, but have other drivetrains numerous times. That can be a one day job, 2 at the most, if you've never done it before. Plan on buying a good torque wrench, but other than that, it'* all standard tools.