With your set up, your engine is making peak HP around 4600-4800 rpm. There's little reason to rev it above 5000 rpm - let alone going above 6250 rpm. If you do, you're just making noise and putting wear and tear on the engine. You'll go quickest by keeping it in between the torque and HP peaks - which in your case is about 3600-5000 rpm. Why do you want to remove the factory rev limiter? If you're going by the stock tach, they are notoriously inaccurate.
As for removing the air pump - you don't need a chip to correct for any effect caused by it's removal; just take it off, block the crossovers and tube to the cats, and put a shorter serp. belt on it.
If you decide to get a chip (the benefits will be minimal with your mostly stock set up), I wouldn't bother with a mail order unit. I'd only have someone local do it so you can actually drive the car and adjust things according to how it runs/drives.