Yes, it is expensive. Yes, it transmits noise. But for the driver who has chased slop out of every other component—from solid subframe bushings to a carbon driveshaft—the Ikusei Final M Size Top is the final piece of the puzzle. It transforms a good manual transmission into a great one.
If you can find one in stock (production is batch-based, typically twice per year), do not hesitate. Pair it with a heavy stainless steel shift knob and prepare to rediscover why you fell in love with driving a manual in the first place. ikusei final m size top
Deducting 0.5 only for NVH and price of entry. Sources: Ikusei Official Technical Brief (2024), personal track testing, and aggregated user data from Japanese tuning forums (Minkara, YAJ Blow). Yes, it is expensive
The addresses three core weaknesses: 1. Material Science Where OEM uses cast aluminum or reinforced plastic, Ikusei uses A7075-T6 billet aluminum for the main housing. The "Final M" goes one step further with a proprietary anodizing process called Ion-Dur that reduces friction coefficients by 40% compared to standard hard anodizing. 2. Bearing Geometry Standard tops use bushings. The M Size Top uses dual-row angular contact bearings —pre-greased, shielded, and rated for 15,000+ shift cycles under load. This eliminates the "slop" that develops over 50,000 miles. 3. Thermal Management Heat soak is the enemy of precise shifting. The Final M Top incorporates micro-fin channels along its base to dissipate transmission heat, keeping the selector mechanism within optimal operating temperatures even during 30-minute track sessions. Technical Specifications (M Size Top Variant) For the engineers and builders, here are the verified specs of the Ikusei Final M Size Top (current production as of 2025): It transforms a good manual transmission into a great one
In the world of niche Japanese automotive performance and aftermarket tuning, few names command as much respect as Ikusei . Known for their precision engineering, relentless quality control, and a philosophy rooted in "kaizen" (continuous improvement), Ikusei has produced a range of components that are often considered "end-game" for serious enthusiasts. Among their most revered—and frequently debated—products is the Ikusei Final M Size Top .
| Specification | Detail | |---------------|--------| | | 7075-T6 Billet Aluminum (body) / 4340 Chromoly (internal forks) | | Finish | Ion-Dur Black or Clear Silver anodizing | | Bearing Type | Dual-row, sealed angular contact (NTN Japan) | | Shift Throw Reduction | 22% vs OEM standard | | Height Adjustability | ±5mm (M-Size specific stack height) | | Torque Spec (Mounting) | 18 Nm (no thread locker required due to precision fit) | | Weight | 312g (OEM equivalent: 178g – the extra mass is intentional for shift inertia) | | Compatibility | Nissan S13/S14/S15, R32/R33/R34 GT-T, Z32 (select models) |
| Brand | Model | Price (Approx.) | Bearing Type | Material | Longevity Rating | |-------|-------|----------------|--------------|----------|------------------| | | Final M Size Top | $590 | Dual angular | 7075-T6 | 10/10 (Lifetime) | | Nismo | Solid Shift (M) | $320 | Single bushing | Cast steel | 7/10 (Bushing wear at 40k mi) | | RE-Amemiya | Spec-X | $480 | Three-piece roller | 6061 alum | 8/10 (Requires annual regrease) | | OEM Nissan | Factory Top | $80 | Rubber bushing | Cast alu | 4/10 (Slop at 30k mi) |