The "amperage" isn't a rating that can break the Arduino, as that's the maximum the power supply is rated for (it will supply a different amperage depending on the load). That being said, you don't want a power supply with too low of an amperage rating, as it may not be enough to run the Arduino. Yours is fine for that purpose.
One thing you may want to watch out for is how much you are running off of the regulated 5V. I tried to run two servos off of 5V regulated from a 12V wall wart, and the regulator became VERY hot. I was lucky enough to feel the regulator before it exploded :P. So you may want to monitor the regulator and assure that it doesn't overheat.
If you're running the blowers from VIN or some other way not through the regulator, you should be fine, just be careful not to overload the power supply.
PS: As a useful bit of info: If you accidentally plug in a center-negative supply, as long as it's not too much power, it shouldn't hurt the board, as there is a diode in place to protect from that (but you should also know that the diode does not protect from plugging cables in reversed to the VIN and GND connections).