Oh your gonna find your pegs scraping sooner or later my friend even if you leave it completely stock. ;D.
You lower it 2.25 you will drag your tailpipe and even grind the exhaust pipe mount right at the same time or before hitting the peg if you hit a dip in a steep turn at speed riding solo with a 240 on it, without bottoming out the tire. I've done this several times and I weigh less than 150lbs.
It only bottoms out the tire with 400+ lbs of combined total weight when I hit some pretty hard bumps or potholes. One time in San Diego on the freeway it bottomed out/rubbed slightly going over a bridge with dips in it at 75 mph with 425+ lbs on it . My pre-load set at #7, links at 2.25, 240 Metz and no progressive spring.
The biggest problem is at slow speeds with a full load 2 up if I hit serious dips or speed bumps it hits the rub indicators which are two tabs that come to a point and they gouged my tire.
Straightjacket posted pics that shows where those tabs are under the fender. You should grind those flat so this doesn't happen to you should you chose the 2.25 drop and come across a big enough dip to cause you to bottom out.
Don't be overly concerned though because the circumstances that it took for these things to happen to me are on the extreme side of things, with exception to the freeway in San Diego. The mountains where I live have really bad roads with steep grades and sharp turns and I was ridding very aggressive.
Other guys have the same set up or even larger tire and very few of them speak of hitting the tailpipe or mount in right hand turns.