My mom has an 08 RR Sport, and she loves it. Although, she bought it new and has only put 3,000 miles on it, no problems so far.
She was afraid of the same thing, electrical problems etc. but two of her friends have 07 and 08s and no problems for them either.
I say go for it, the RR is a hot car, although the 2004 is the old body style, right? They may have also addressed and fixed the problems in the newer models and not the older ones?????
I'd stay away from the older models, especially if out of warranty.
E93: Montego/Cream <---- E46 (Coupe): JB/Black <---- E30 (Cabrio): Alpine White/Black