Firstly I would suggest you sell the ES privately; $17000 is probably more than the car's worth considering you can pick up a brand-new ES sports with free CVT upgrade for $19990 driveway (or less...).
Going on the figures you've shown, they're charging you full-whack for the RA.
Two things to consider: you can pick up a new MY14.5 RA for $34-35k and the MY15s will be available soon(isn) at $39990 driveway.
If you sell yours for $15k, you would need $20k or less for the MY14.5 RA (there are still some around), that extra $3k will pay for your first year's insurance
A good late-model second-hand RA will be under $30k, will still have plenty of warranty and someone else will have lost the value on depreciation, not you!
If you pick one up for, say $27k, all of a sudden you only have to find around $12k to buy the RA - a whole lot more affordable and just as much fun...
As Craig said, first stop is the insurance company (and do shop around...).
I get 9.5 - 10.5l/100Km regularly - just leave it in normal drive when you're commuting and leave the sports mode alone until the weekend and you'll find they're not that expensive to run.
Be warned, they're a popo magnet!
As far as 'living' with an RA - no question - the NA Lancers are excellent cars (I should know, I've had three!), but the RA is just nicely sorted - heavier, sure, you can feel that when you drive - but a lot more 'planted' on the road with noticeably better cornering & braking. There's plenty of cars out there that will beat you at the Traffic Light Derby, but not many for the price of the RA.
Plus, you'll have a stupid grin on your face for a couple of weeks after you buy it!
Ultimately if you can afford it, go buy one - you won't regret it...