I have a 2006 Nissan PF, SE, V6, 4WD, Auto. My coil springs seem weak. When I go over a dip in the road or have a full compliment of passengers, the rear seems to bottom out, that is the springs completely compress. I recently replaced the shocks with rancho's but now it appears the springs may need to replaced as well. My question is can I replace them with a stiffer spring?, where can I find them?, what do I need to steer clear of when doing so? Or should I just replace w/OEM?
Please advise,