Aggressive Rent Increases

I wanted to get some information on rent increases. I just bought a park in Arizona and the former owner had the rent all over the board. It was ranging form $180 to $300 per space. Only one space is paying $300 and all the rest are $250 and lower. My question is that if I raise rents to $275, everyone will have a an increase and the $180 per month tenants will have a huge percentage increase. However, the market rent is north of $375 and as high as $550. I have some vacancy now and think I will get more once I increase rents, but my residents will not be able to move to another park and pay less than the $275. I remember Frank talking about sending a list of all the parks in the area and their phone numbers and lot rents. My attorney said I can be aggressive, but I may not make many friends in the park. Last, as I move new homes into the park, I would charge them $300. I would like ALL rents to be the same, but could keep them slightly lower for existing tenants. Any one have any ideas?