Sound from Passenger Side

[tifosi00]

Hello,
Can anyone help me with this? I have explained it to the dealer numerous times, only for them to tell me they don't hear anything. I have a 2000 base boxster that has been lowered with aftermarket rims. I get a loud humming noise when in either 2 or 3 gear around 3,000 rpm coming from the passenger side. When it starts to happen, if I either rev the engine more or take my foot off the gas it will stop. It has actually been happening for a couple years now, before and after I lowered the car, through 2 different sets of tires, so it's not the tires. I am thinking it's a bearing, but that wouldn't really explain why it goes away when I either step on the gas more or let off the gas.

Any help would be greatly appreciated.

Thanks!