First Time Owner 98 318Ti

[NickDub]

Whats going on 318ti.org, my name is Nick, I am a proud new owner of a 98 318Ti, Traded a turbo Talon AWD for it and love it. I am new to bimmer'z so I will be browsing a lot and asking questions. Here is some info on the car

1998 318Ti
5-speed
178k on Body - 78k on motor
H&R Lowering Springs w/ Bilstien Shocks
BBC 17" wheels w/ Z Rated Tires (smooth ride)
Its got a higher ratio rear end unless 75mph at 4200rpms is normal =-?
Silver w/ Black Leather


Few Issue's
1) Do 318Ti's come factory with a keyless entry system or alarm? (got 1 key only)
2) Hearing a noise while driving from back of car. Its something from the rearend/wheel bearings/or brakes. Any common issue's with the rear drivetrain?
3)I desperately need a wiring diagram for the stereo wires as the thief who took the stereo proceeded to cut the harness off. =(

Any help would be greatly appreciated


Thanks for the space and time 318ti.org!!!