Glad they got rid of the SIR...

[mossaidis]

^^ agreed....

Highlights of B18C Spec R compared to standard B18C GSR

1. Camshaft - Wide-angled, high-lift, high-durability camshaft *
2. Exhaust Valve Spring - High-lift, dual-layered spring *
3. Spark plug - High-heat-type #7 platinum plug *
4. Engine Stiffener - Aluminum die-cast, high-durability, one-piece type *
5. Crankshaft - Full-counterweight, 8-weight, high-output, custom crankshaft
6. Connecting Rod - Custom TypeR rod, high-durability, lightened *
7. Pistons - High-compression, low-friction, custom pistons *
8. Inlet Valves - Lightened inlet valves
9. Intake Manifold - Custom tuning, single-port type. #
10. Throttle Body - 62 mm (2.4 in) wide-mouth throttle body. #
11. Inlet Valve Springs - High-lift, flat-surfaced, dual-layered spring *
12. Port Buffing done by hand
13. Fastening of Connecting Rod done with micrometer.
14. 98spec engine has stainless steel 4-1 exhaust manifold *

* - irrelevant considering current STL rules
# - irrelevant if IM/TB allowance existed

So....crank, lighter valves, "hand" port buffing... that's significant.