Originally Posted by
Nitrofaint
5w-20 is used to meet LEV (low emissions vehicle) standards and is suitable for DD'ing. The advantage of using 5w-30 would provide you with better protection during summer months, or if you are heavier on the gas pedal, since it will not burn off as easily.
Personally it's better to be on the safe side to have the right viscosity to protect you when you need it the most (at higher rpms)
In addition to weight, certain brands of oil will burn-off at a faster rate than others.
The cam galling issue was inherent to the 02-03 model k20a3's, some rare occasions on the 04-05. I am unfamiliar with the k24 having any issues.
A k24 Will produce more heat, which will take it's toll on the oil at a greater rate than any k20 if they are both under the same load/environment conditions.
I would recommend 5W-30 for your friend for his engine.