I recently installed the 412s (412-4067-HD)in the stock 11" height along with the progressive drop in fork springs 11-1527 for stock height on my 2009 Nightster. I weigh 190lb and have the shocks set on the lowest pre load setting. What a difference the combination makes. Responsive to bumps and pot holes without bottoming out or bouncing me out of my seat. I really enjoy the Nightster and these changes (relatively inexpensive and easy to perform) made a significant difference in comfort and handling. Don't know about the lower kits but I expect you would have similar results.

 

Ditto save for the Belray fork oil. No more scrapes around corners or off speed bumps.

 

Ok so im looking into getting 412 HD. I ride by myself most of the time, but if my wife rides with me i want to have that extra suspension in the back. Between the both of us we weigh maybe 425. I want the bike to have the same/similar height to it now but also be able to be adjusted properly for when im by myself, so does anyone have any suggestions on the length to get.....or what stock is right now? BTW, its an 09 nightster...any help would be great