I, myself would not go to a 200R4 ... because the Overdrive in it is 33 per cent. With your rear end ratio of 3.23, the ratio in OD will be almost 2.10
With a final drive ratio of 2.10 ...
Your RPMS could be very low and lugging the engine. MPG very well could be worse ... a 3.70 rear ratio would be way more acceptable.