I'm thinking about going ahead and doing the plenum fix. No performance problems, but using maybe a quart of oil between oil changes. Plus, I'm just curious to see if I will notice a difference in anything after its done. I figure there are a lot of folks who've done the plenum and the heater core. Trying to see how much time I need to set aside.I did my heater core a little while back. So, which takes longer, and by how much? Also, the only thing that concerns me with the plenum fix is possibly getting water in the oil. If I take the rad off, will all of the coolant be out of the intake when I pull it off? Thanks.