Enter Millionaire City
Open Cheat Engine
You will need to have ONLY ONE Triumph Arch (decoration) in your city to get the address.
First scan "700000" (Change to 8bytes)
3 address returned. Double click the address that ends with "79C", so it appears in the Edit table. (If you do not see any address ending with 79C, just REFRESH Millionaire City and ReScan. You should see it now)
Change the address from 79C to 7B8. Meaning: xxxx79C > xxxx7B8
Notice the value is 1. Change the value to 1000
Now, enter your friend city then go back to your city
Now ALL the HOUSES will have +4480 bonus. Works and Saves. Have fun.