I bought lowering brackets from STREETBOOGIE, dont know if he is still around, but I only lowered the rear. I am 5'7 200lb.
I have some occasional tire rub on the 12in deep/high potholes here in NYC. Sometimes my sceptres drag on tight turns, but they are LONG and low anyway. Other than that, I ride twisties in the mountains, and split lanes in the city, if anything they helped lower my center and add more grip to my rear brake. (pre brackets, I lost rear traction alot when rear brakeing in a tight turn... not anymore)
OH, Also depending on how low you go, I'm -2in, You have to trim the fender on the side where it meets the chain guard under the first frame/fender mount bolt. It can compress, and buckle the fender and chainguard.
