Larger tires...computer recal?

I ordered new wheels/tires for my '02 disco. 16" wheels with 31.5" tires. I already installed medium OME shocks/springs for about 1.5" of lift. I have yet to install the 1" spacers but will do so soon. Now...when it came time to talk to my tire dude about my 31.5" tires I've yet to install, he told me I'd have to have Rover recalibrate "the computer" to not run into problems. What does that mean??

Also, anyone have tips for trimming the front portion of the front wheel well. We gonna rub, even with 2" of lift.

Here is link for the fender trim. If your 02 is anythig like my 98 was the larger tires will result in a much more accurate speedometer/odometer reading. Calibrated mine to a GPS reading with the new tires (31.5"). Indicated reading 55 mph, actual 56.5 mph. Not enough to worry about.

http://www.fag.hiof.no/~frodehaa/forandringer/245-75.htm

I think you got some bad advise, you do not have to recalurbrate the ECU for the larges tires, just spend more money on gas.
Question, why did you install medium coils then turn around and order 1" spcers, and which OME shocks did you install since they don't make medium duty shocks? Are they the 107/108 HD shocks or the 107C/108C which are the light duty?
Mike

Mike, I bought the Medium duty OME spring and shock kit from Atlantic British. It all came in a package deal. Having spoken with a couple guys who've run the HD OME springs, they all said the HD springs made their discos ride like lumber wagons. I wanted to retain a few road manners. So, I was advised to complete the extra lift with the spacers. Since I don't plan to add a bunch of superfluous gizmos like brush bars, winches or full roof racks, I didn't think running slightly lifted Mediums would be a big deal. I'm not overloading this thing anyway.

Disco's suck for the fact I can ask four guys the same question and get four answers. My Jeep Rubicon was much more strait forward to tweak.

Thanks for the FYI on the ECU. That definately sounded suspect when I heard it.