I don't regret it, I lowered front and back on my Deluxe but only went 1 inch, used Progressive 422's rear and their monotubes in front, I haven't had any problems, about 4k on them.
I just raised the rear 2 turns this morning from all the way lowered. I loved the look but them damn fishtail tips ain't cheap! I got tired of scraping them all over the place. Took it for a ride for half an hour and it didn't scrape like before, except going in and out my driveway. I'll be saving my pennies to buy air ride in the future.
Lowered Night Train. The ride is a little harsh. Midway between a rigid and the way it was. No handling problems, but you have to remember what you're riding.
I have a Shotgun Shock and I played with different heights after I installed it.
That was two years ago, and now I just leave it at stock height for maximum comfort and best handling - as intended.