It depends on how you have it setup, and what your timing strategy is. If you don't know your actual/physical injection start point, it's not really worth changing anything. If you've set up your injector timing to specifically coincide with certain valve events you'll want to make the appropriate adjustments. If you are going to a bigger cam idle, driveability, and economy will probably suffer somewhat. However, if your injector timing is less than ideal, the change will be more dramatic than it needs to be. I found that running very large cams is a good motivator to figure out injector timing and get it right.
