Hi Karl.
the DV shouldn't give you anymore lag, is it possible that it didn't quite seal when installed? The cam follower is defo worth checking. They do wear, and it's a quick job. They wear more with an uprated pump but still suffer even with std.
Don't worry about the 192 bhp reading. It's a very crude measurement, you're well in the ball park figure so nothing to be concerned about. When mapped, I'd be looking at the lambda regulation figures to make sure the MAF is correctly reading the increased airflow figure.
Thanks, Rick