The NISMO O.E. springs & shocks are different from NISMO S Tune .Several people have reported issues off no drop or slight increase in ride height. With the O.E. setup.Please see attachments for a comparison off stock vs. NISMO S Tune springs and swaybars. The info for stock spring rate is from Eibach where it is compared to their Pro Kit.
Scan0003.jpg PRO-KIT—NISSAN 2009 DATA: TECHNICAL INFORMATION FRONT: OE rate: Linear 74 N/mm (422 lbs/in) PK rate: Progressive 42-84 N/mm (239-479 lbs/in) Tubing: None Bump-stop: OE Damper: OE OE wheel center to fender: 381mm (15.0in) PK wheel center to fender: 360mm (14.1in) Front Alignment: OE Camber = -0.55 +/-0.75 deg OE Caster = 8.15 +/-0.75 deg OE Toe = 0.04 +/-0.04 deg PK Camber = -1.1 deg PK Caster = 5.7 deg PK Toe = 0.04 deg Approximate installation time: 1.5 hr. PRO-KIT can be aligned to all OE alignment specification except caster. Recommend Pro-Alignment kit 5.72135K. REAR: OE rate: Linear 79 N/mm (450 lbs/in) PK rate: Progressive 38-93 N/mm (217-530 lbs/in) Tubing: None Bump-stop: OE Damper: OE OE wheel center to fender: 377mm (14.8in) PK wheel center to fender: 357mm (14.0in) Rear Alignment: OE Camber = -1.6 +/-0.5 deg OE Toe = 0.085 +/- 0.035 deg PK Camber = -2.5 deg PK Toe = 0.11 deg Approximate installation time: 1.0 hr. PRO-KIT require Pro-Alignment kit 5.72260K or 5.72265K.
Sway bar comparison
Front: 1.1" (27 mm) hollow steel, 5.3 mm wall thickness
OE: 1.0" (26.5 mm), 3.5 mm wall thickness
Rear: 1.0" (25.4 mm) hollow steel, 3.5 mm wall thickness
OE: 0.9" (24.2 mm), 3.0 mm wall thickness
Hope the attachment up loads . If it doesn't the S Tune spring rates are 450 front ,508 rear.