CORNFLAYKES,
Like others have said - do what makes you happy as long as you can aford it. But here's my 2 cents:
Personnally I like the looks of the P5 over the sedan - when I went shopiing I had both the MP3 in mind, and the P5, but whe I saw the 2 cars, it was the P5 for me.
One thing that would deter me on trading so fast, is that I will be bound to lose my shirt on the deal. The fastest depreciation on a car is the first couple years. I've got to beleive you will get killed trying to sell or trade so soon - but maybe you lease or have a special arrangement you can get out of your deal easily.
Lastly, a 200+ hp turbo is tempting, but will you need it? I mean for me, 90% of the time I can use most of the P5's potential. What I'm saying is, how fast do you need to go on the street? You have enough speed to get you in trouble now if you try really hard, right? If you plan on racing on long tracks, well then that's different. Street, and short slalomn racing, I don't think you will gain that much.
Good luck!
- Woody