Has anyone tried to change the Tein basic spring/shock combo?

I drive a G35 and have GT Spec bars everything is good when I'm driving alone but when I have passengers and hit a dip my GT spec bars scrape.
I already have the rear at their highest settings.

I figure I could use some stiffer springs nothing crazy but definitely need something more sport oriented.

 

Tein tell's use that their Basic coilover system for the 350Z has a limitation on spring rate changes of +or- 56lbs. The setup comes with 504lbs springs, you can call Tein and get the part numbers for the 560lbs spring swap. Then call any authorized Tein dealer and pass on the part number to them, give them at least one day to call Tein and get a final cost to you.

If a 56lbs rate increase is not enough, pull the coilovers and resell them so you can get setup that truely meets your needs. Keeping in mind that their is such a thing as too much spring.

 

Thanks for the info.
Looking for stiffer spring rate without having to lower the car more would be great

 

Tein Flex's. 670 pound springs lol. 1800 bucks too tho >.<

 

and absolutely nothing to do with tein basics....aside from them both being green