I exchanged the 612 for a 1480 in my Euro R107 300SL and it was plug and play with much better sound.

@JamesDean: Did you install additional speakers? The unit supposedly handles up to 4 speakers (and has a plug for an additional set of speakers) but only has 2x25 watts, so I wasn't sure if this approach or adding an additional amp were the best route to go.

With the roof down the small SL front speakers are very much at their limit...