Those are tough constraints. I would just keep your S2000 if you like it and focus on narrowing down your sedan choices.

 

Buy the best four door car for work, buy the best other car for yourself. If you compromise either, you're going to either overpay or not be completely satisfied.
I dunno what kind of clientele you'll be chaffeuring around, so dress accordingly. If you're shuttling suits, then an acura, lexus, etc will be better than getting a subaru or accord.
A used TSX is really a great buy as it has few known (non devastating) problems unlike teh TL and should promise a good drive. Otherwise take your pick from teh usual suspects like the camry/accord/altima/malibu/500/maszda6/etc. Also, if it's going to be for work, be sure that it's somethign reliable and economical (not just talking gas). I talked to a customer once as she was a real estate agent, she used to shuttle people around in her S class but found that it would need to go into the dealer frequently for work which really got old. A vehicle with a utilitarian purpose cannot be a primadonna. Also, how is an evo a good idea for a car for work?
As for your second car, choose away, lol.

 

You really think you'l get a good price on an IS-F? I thought those would be MSRP for a while

 

Well I won't have clients in my car, so the noise and comfort factor will not come into play, and the RS lacks most of the bling (namely the giant rear wing) of the standard EVO.

 

Not with an M3 being $55k

 

Picture this in your driveway.

2009 White IS-F
2007 GPW S2000

If your looking for a little more excitement out of your S2000 Supercharge it!

 

Ah, gotcha.

 

That sounds terrific! But unfortunately I would also have to picture an extra $25k in my bank account

My ultimate scenario would be to have a high performance sedan (IS-F, M3, RS4, etc.) beside a fun roadster, but I also like to live within/below my means, so I do not want to overextend myself.

 

If I were faced with that choice, I'ld go for the Elise + Evo combo! The Lotus is perfect for a weekend toy, and the Evo would be a fun daily driver.

 

i agree. hands down.