Is there any difference in the engine at all between an auto and manual in an RS200.

as far as i know the manual is 10bhp more with a slightly different head setup from what ive read.

Different internals in the auto engine due to the lower rev limit,, also with most autos they tend to be about 20% less power as a rule,,,

The auto has a lower comp ratio. the manual is 11.5:1 and the auto is 11.1:1

Different camshafts and profiles.
Different valves (Manual had titanium valves)
Different pistons (CR is only 11:1)

Automatics normally have less power than a manual due to the fragile nature of automatic gearboxes.

make them same torque but at lower rev think it's 2k rpm lower than manual