318 runs real load and shakes like crazy

5 pin. Forget that. If you have a FOUR pin ballast, (older) you need a FIVE pin ECU. A newer and improved (OEM) FOUR pin ECU will work with EITHER a 2 or 4 pin ballast.

There is NO way to tell a 4 pin ECU from a 5 pin by looking. Many 4 pin ECUs have 5 physical pins.