I think you are also wanting to do some major work on your own car so when you take it out for the first time your smile will be wide and you get that amazing feeling of achievement which you don't if you go out and buy a GT3.
I can see that..I did bore work on a Triumph bike I had and it transformed the bike no end..it felt good.
But Porsche make very good cars and improving them at this level is expensive and difficult.
I suggest you look out for a low mileage, babied 986/7
S with a blown engine and transfer your engine into that.
That way no cost of body work and no brake/suspension upgrades, just a brilliant useable car that will blow most other cars to bits.
Good luck what ever you do.