LOL 20L per 100kms towing. My SRT gets that city driving when given a hard time (and sometimes worse).
Had a 700L signature that weighed in at 2.5t and it was 22 to 25l per 100Kms.
Fixed it by selling the signature and buying a 45ft Sea Ray that is at moored so no more towing the boat only the jet ski now and the weighs nothing.
If you are worried about the fuel consumption maybe a V8 SRT isn't for you if not go for it
.
I had 5 Kenworth semis ranging from 550 to 620hp right up on there weights getting anywhere from 2.2 to 2.4kms per ltr @ 45T doing local/city work so the SRT isn't that bad.
The way I see it is I like my V8's so thats how it is.