I'm afraid that £350 won't buy much on a 24m contract. All the depreciation happens when the car is new and this contract doesn't run long enough for it to start to even out. In my opinion it isn't very sensible to change at 2 years if the car will have done only 40,000 miles.
CO2 is 258g/km so BiK tax is payable at 35% of the £23,801 at your highest tax rate.
"Spread rentals" is the term for your requested profile 3x23 and means you pay 26 months rentals on a 24 month agreement. We don't do these but on 3x21 the rental incl maint is £628.00, so an arithmetical calculation would make the spread rental about £580 or thereabouts.
The Focus RS is off our database now and we won't fund used cars or imports, but a Mondeo 2.0 Zetec 5 door is £444, and the new Focus 1.6 Zetec 5 door is £315.