I'm probably late now, but just in case someone finds this in a search...
Megan Roll Center Adjusters are junk!
They do nothing but move the arm down, so they
look like the roll center was adjusted but it is not, the pivot point stays the same as stock and does nothing to fix roll center.
Roll center is determined by pivot points, the Megan's shank is the same length as stock (you want a longer shank), so it does not move the pivot point down lower like you want it to.
If you get bumpsteer, it may be time to space your tie rods down to get it parallel to the ground.
Also, if you want a lot of roll center adjustability, do what's done in this guide:
http://www.nissanroadracing.com/showthread.php?t=1407
I'll be doing it once I install my coilovers.
I read that thread many many times, so if you have any questions about the modification, just ask me!