From the RD Sport website, the following is RD Sport's description of it's M6 and M5 engine upgrade, aka "Motor Tuning" package RS58:
"True to its tradition, once again RDSport discounts the easier forced-induction route and pushes the envelope of its normally aspirated motors to a new level with 650hp 5.8L RS58 stroker motor.
The V-10 RS58 uses much of the same technology found in the latest F1 motors: billet crankshaft, billet rods, and a set of forged pistons that are amongst the lightest to ever find their way into a production-based motor.
The ported cylinder heads boast 17% more efficiency than the stock ones, and this is mainly obtained through the use of larger valves and modified cam profiles.
The RS 58 M5 Package comes complete with a full exhaust system, including Race Exhaust Manifolds, Metal Matrix Sport Catalytic Converters, Sport X-Flow Midpipe and Competition Rear Silencers with Quad Tips."
Pages from the Company's Brochure show some of the options available...
Added these interior shots and engine pics. Note the underside of the all-carbon-fiber hood…also note the two plaques indicating "001 of 150". Optimism abounds!!