ISR Performance Pro Series Coilovers - Nissan 350z Z33 - IS-PRO-Z33

The ISR Performance Pro Series Coilovers for the Nissan 350Z Z33 (IS-PRO-Z33) represent ISR's step up from their popular Basic coilover line, engineered specifically for Z33 chassis owners who demand better damping control and improved handling whether they're carving canyons, hitting the autocross lot, or pushing hard on track. Building on years of experience with their entry-level coilovers — including use on professional Formula D drift cars — ISR designed the Pro Series to deliver a noticeably more refined and capable suspension package without abandoning daily-drivability.

Key Features & Benefits

• 32-Way Adjustable Damping: Fine-tune compression and rebound across 32 distinct settings, letting you dial in a compliant street setup or a stiffer track tune without swapping hardware.
• Mono-Tube Shock Design: A single-tube construction separates the oil and gas chambers for more consistent damping performance and better heat dissipation compared to twin-tube designs — especially important during extended track sessions.
• 14K/12K Spring Rates (Front/Rear): The matched spring rate pairing is chosen specifically for the 350Z platform, providing a firm yet controlled ride that keeps the front end flat and steering response tight — exactly what verified buyers have reported in real-world use.
• Pillowball Upper Mounts: Front pillowball upper camber mounts replace the OEM rubber-isolated top hats for a more direct connection between the chassis and suspension, reducing flex and improving steering feel and camber adjustability.
• High-End Japanese Bearings: ISR specifically highlights the use of high-quality Japanese bearings throughout the Pro Series, contributing to smoother damping action and long-term durability.
• Street and Track Versatility: Unlike coilovers optimized purely for competition, the Pro Series is designed to provide a comfortable ride while still improving handling — making it a practical upgrade for a Z33 that sees mixed-use duty.
• Upgrade Over the Basic Series: The Pro Series builds directly on the proven Basic platform that ISR ran in Formula D, adding refined damping, higher-spec bearings, and pillowball mounts for drivers who want measurably more performance.

Specifications

• Part Number: IS-PRO-Z33
• Damping Adjustment: 32-way
• Shock Design: Mono-tube
• Spring Rate: 14K front / 12K rear
• Upper Mounts: Pillowball (front), camber-adjustable
• Bearings: High-end Japanese bearings
• Package Dimensions (as listed): 28.40" H × 18.30" W × 8.50" D

Fitment

The ISR Performance IS-PRO-Z33 coilover kit is designed to fit the Nissan 350Z Z33. Multiple sources also reference fitment compatibility with the Infiniti G35 Coupe (which shares the Z33 platform). If you are unsure whether your specific model year or trim is covered, contact ThreePiece.us before ordering — our team can verify fitment for your exact vehicle. Note that this kit is listed as designed for off-road and competition use only per ISR Performance's product disclaimer.

What's in the Box

• 2× Front coilover assembly
• 2× Rear coilover assembly
• 1× Spanner wrench set
• 10× Top hat lock nuts

Note: No installation instructions are included in the box per buyer reports. Installation is straightforward for those familiar with coilover suspension work, but professional installation is recommended if you haven't replaced coilovers before.

Why Buy from ThreePiece.us

At ThreePiece.us, we specialize in performance suspension and wheel fitment — so when you have a question about whether the IS-PRO-Z33 is right for your build, you're talking to people who actually understand Z33 suspension geometry and coilover setup. Every order ships free, no minimum required. Need to spread out the cost of your suspension upgrade? We offer financing through Affirm, so you can get your 350Z sitting right without waiting. Have a fitment question or need to confirm G35 Coupe compatibility? Reach out before you order — we're here to help you get it right the first time.

Frequently Asked Questions

Q: Does this kit also fit the Infiniti G35 Coupe?
A: Yes — the IS-PRO-Z33 kit is listed by multiple sources as fitting both the Nissan 350Z Z33 and the Infiniti G35 Coupe, which share the same Z33 platform. Contact us to confirm fitment for your specific year and variant before ordering.

Q: What spring rates does the Pro Series use on the 350Z?
A: ISR specifies a 14K front spring rate and a 12K rear spring rate for this application. These rates are tailored for the 350Z's weight distribution and are firm enough for responsive handling while remaining manageable for street driving.

Q: How is the Pro Series different from ISR's Basic coilovers?
A: The Pro Series is ISR's higher-end line, featuring improved damping control, a mono-tube shock design, high-end Japanese bearings, and pillowball upper camber mounts. ISR's Basic coilovers were used on their Formula D competition cars — the Pro Series builds on that proven foundation with upgraded components for drivers who want more refinement and adjustability.

Q: Do the coilovers come with installation instructions?
A: Based on buyer feedback, installation instructions are not included in the box. Coilover installation on the Z33 is considered straightforward for experienced DIYers, and the included spanner wrench set covers the tools needed for height and damping adjustment. If you're not familiar with coilover installation, we recommend professional installation to ensure proper alignment afterward.