Gen 1 Horsepower

I currently own a 1998 RL with 210k miles. I've found a 1 owner 2003 with only 71k miles, but it does not seem to have as much power as my 98 while it is rated 15 HP more. I have not taken it to a mechanic to check it out yet, but was wondering if any one has knowledge or experience with the different model years of Gen 1.

Also, while idling in Park, you can hear and feel a "click" in the shifter console when you step on the brake. Any idea what that might be?