Having owned from new a IS200 Sport '02' for 2 years and then from new a IS300 '04' for 3 years, and a high mileage driver at that, if your budget can stretch to buying a IS300 (a lot of good priced ones out there) then I would go for the comfort and refinement of the IS300 . This isn't just a IS200 with a bigger engine ! When my 300 was in for servicing, they lent me a 200 and the lack of comfort and quietness was very noticeable, I was glad to get back into my 300. I'm not harping on about the obvious power difference here that would be unfair, because my 200 Sport was great fun indeed and once when the sport was in for servicing I was lent a SE and that was even more inferior to drive with loads of body roll etc. :duh: , the SE was an automatic and oddly enough was much quicker from 0- on accelaration than the manual 6 speed of my sport!
The IS300 is an auto but does come with manual gears on the steering wheel and an LSD on the rear wheels !
This maybe of some help towards your decision and may also 'spark-off' some heated debate , but overall your driving style could be analysed as follows:
1/ Concerned MPG driver, not too bothered about gismos = IS200 se
2/ Likes gismos and looks, may modify later, looking for good solid handling, don't mind changing gear a lot and could do with a 7th gear for motorway driving = IS200 Sport
3/ Same looks & gismos as Sport, Sod the MPG (mind you I get 32 at max), great for around town with no constant gear changing, likes comfort and refinement & POWER! = IS300