Goodness me! You have many questions, Grasshopper!
I don't know what a "soft window" is - I could guess, but I'd rather you tell me.
As for the other pieces, like lightweight bumpers, RS door panels, etc., all that should fit on a targa as easily as a coupe.
Two suggestions:
1) Search the board under "weight," "weight reduction," "lightweight," etc.
2) Go to this link:
http://gt-racing.com/
Good luck!
