The easiest way is to replace an existing car in the carlot by a new code - buy the replaced car - then revert back to the original code. (You can of course simply add the correct line in a free slot.)
In this example we will replace the Nissan 240sx with the Koenigsegg CCX.
0. What you need:
You need a memory editor: ArtMoney, tSearch or any other MemEditor with a decent Hex View will do fine. I'll use ArtMOney v7.17.
1. Initial setup
BACKUP your career!
- Start NFS Pro Street, load your career, then switch back to Windows (ALT-TAB).
- Open the MemEditor, then open the process 'Need for Speed Pro Street'.
2. Find the region to edit
The address will change each time you load NFS ProStreet, so we need to search for a known value (ArtMoney doesn't have any hex search afaik, so we need to search an integer).
- Search for this Integer: 305419896 (this is 0x12345678 - the start of the carslot region).
You should end up with 2 maybe 3 results.
- open the first result in memory view by selecting the value then press CTRL-M (or right click -> memory editor).
- Change 'number of value columns' to 24, so it will look like this (every line now stands for a carslot, if it doesn't look anything like this try the next value):
*img515.imageshack.us/img515/6539/memeditqw0.th.png
- Scroll down 115 lines (we skip the pretuned cars) until you can see 72000000:
*img108.imageshack.us/img108/2845/memedit2ch5.th.png
3. Replace the code
- Replace the 2 codes FC2B6FA8 FC2B6FA8 (logo and carcode) for the Nissan 240sx with the codes for the koenigsegg CCX, which is A6DCC132 A6DCC132.
*img49.imageshack.us/img49/6162/editedyz6.th.png
Make sure you complete the change of the number in the last field by pressing 'enter' or selecting another field.
4. Buy the car and clean up
- Switch back to the game, go to the carlot, buy the car.
- Switch back to Windows and restore the original Nissan 240sx code.
5. Have fun
Go try your new car
But don't forget to save your career first. just in case you crash your game.
Greets
cparty