The FCC in the USA allows up to 500mW of RF with an effective radiated power 
(ERP) of 1W when using Spread Spectrum. (The ERP takes into account the gain 
of the antenna fitted). The European version must abide by the European 
regulations (EN 300-328 ) which limits the power output to 100mW ERP but 
because the Spektrum DSM system uses Direct Sequence Spread Spectrum a 
limitation of a Power Spectral Density not exceeding 10mW/MHz also applies.

What effect this will have as a direct comparison between the US version and 
the UK version is at the moment unknown but anticipate a reduction in range.

Think I'll wait a bit longer before jumping!

CM