That is alot of information to transfer here. I would recomend a book for you. "Original Pontiac GTO" The Restorer's Guide '64-'74. By Thomas DeMauro. Great reference book.
The factory tires and rims from a 2001 Pontiac grand am cannot work properly on a 2003 Pontiac grand am.
These have been refurbished and tested by JL Audio directly with factory specifications. 100% JL Audio parts
The Pontiac Montana does not come with a factory installed amp in the sound system. The wiring goes directly from the radio to the speakers.
Re-manufacturing
P225/60R16 is the proper factory tire size.
Rims and tires from a 2001 Pontiac Grand Am will fit on a 2003 Pontiac Grand Am. They have the same lug nut pattern.
Fendi factory is a wide range outlet where you can find sophisticated clothes and high class accessories. The Fendi factory is located in Rome and is established in the year 1925.
Yes, it came with one.
No, from the factory Asters were all four cylinders.
no
From the factory it was rated at 400 horsepower.
Have a Pontiac dealer's mechanic look it over and tell you.