A replacement to the range-topping RL sedan is being readied and is expected to go on sale before the end of 2012.Following their announcement that the NSX Concept, ILX Sedan and 2013 RDX will debut at Detroit, Acura officials have confirmed to Inside Line that a successor to its range-topping RL sedan will debut next spring at the New York Auto Show and hit the showrooms by the end of the year as a 2013 model.Larger than the current RL and perhaps with a new nomenclature, the new model has been described as having the agility of a BMW 5 Series with the cabin space of a 7 Series.Customers will have a choice of a new V6 gasoline engine or V6 hybrid system with super-handling all-wheel drive (SH-AWD). The latter will get a high-performance lithium-ion battery and according to Honda it will provide: \"acceleration equivalent to V8 engines, as well as fuel efficiency equal or superior to inline four-cylinder engines.\"This is achieved using a 3.5-liter V6 engine with an electric 4-wheel-drive system, 20kw motors on the rear wheels and a 7-speed dual-clutch transmission.Honda\'s upscale brand wants three distinct four-door models, which Acura officials say are \"too close in size.\"There needs to be more differentiation between the TSX, TL and RL, base prices for which currently range from $30,695 for the 2012 Acura TSX to $48,585 for the 2012 Acura RL.A product planning executive informed Inside Line that: \"We will ultimately have three sizes of sedan - entry luxury, mid luxury and high luxury.\"These could well be the ILX Concept as the base, the RL replacement as the flagship and a combination of the TSX and TL as Acura\'s mid-level sedan.