Few simple ideas...

[SAFC]

First idea is new cars, things like aston martin, mercs, lambos, bugatti veyrons, and various other supercars, users could have a zip/rar file to download to be able to have those cars available in the game. Presuming theres no copywrite laws against it, but even still you could just tweak a few things on the car to make it look the same but with a couple of differences, and obviously names changed, like Lambourdingi.

Another thing maybe have an option to buy a license for a few million to fly the fighter jets and hunters. One license for hunter and one for the fighter jet, and if they lose the jet or hunter they need to buy a new liscense to fly one again. But only allowed to buy 1 of each every 5 hours or so.

I also think a good idea would be to change the bank limit for pro accounts. A standard account in the 24-7 is 15mil. It doesn't take long to make 15mil, then waiting for a pluspoint to get a proaccount. then having to wait 10hours to get past 20mil. It doesn't take long to get that extra 6mil after buying the proaccount. So maybe up it to 25mil then 50mil then 80 then 100 then up in 20s.