scraping the pegs and some wobble could be some side affects if you guys ride aggressively.
I had a few wobble moments on my aero in some corners until I cranked the preload up to 3 (I'm a 135lb guy) and still scraped the pegs. no way you'd be able to do much more than a leisurely cruise with the forks slid up in the triple tree and soft n' saggy shocks.
I'd try to find a lowering kit for the rear, that way you can keep a longer shock which is going to have more travel for a much better ride and no bottoming out. still have the issues of scraping though.
also make sure you're sticking with a smaller tire in the rear. maybe the front too if you can find one.
If I take the preload up will it give a stiffer ride? With my back problems 2 has worked great but as I'm riding more I find myself doing turns faster and don't want to bottom out but I want to keep the ride soft enough for my back, maybe try 3?
I'll give my son this info when he gets home in 2 weeks, he now rides 2 up a lot with his girl friend and could probably go up a little an still flatfoot with her on the bike, so maybe go to 3 for him also so that its not too high when he rides alone? His GF only weighs about 120.
Good to know info! Never thought about wobble because I never went that fast but knowing my son it would probably affect him a lot more.
BTW, I'm about 150 and my son about 145. His ACE does have one size larger rear tire than my Phantom.