Ditto to Brad's last comment (man you keep beating me to them, don't you EVER log off?)
I've also read of many hobbiests experiments with larger pumps on the Berlin skimmer, specifically 9.5 and 12 models. The concensus has been that after the MAG 7, the increase in skimming is minimal at best, just wasting money on a larger pump, and using more electricity to run it.
For the difference in price between a MAG 7 and MAG 9.5 ($25) your money would be much better spent on a Kent Turbo Venturi to replace the factory Berlin venturi. This upgrade, coupled with the MAG 7, apparently causes the Berlin to skim like nobodys business!