I am running megan racing springs on my car right now, and have been for over 2 years now. I have not too many complaints with these, except for harsher ride. That being said, most springs that lower the car 2" will have a harsher ride. If you buy these springs, look into a good set of dampers within 10,000 miles. I ran my stockers in there for about 20,000... and only one of them were pretty shot when I removed them. I have the SVT shocks/struts with the megan racing springs and an SVT rear sway bar, and I'm quite happy for the moment.
And I'll second the good input for the Megan Racing exhausts... I have the axle-back exhaust for my wife's Sentra.