most undetectable mod menus have RP features! public mod menu's that i would recommend would be either d3sk1ng or Nullify (d3sk1ng runs at about $15-25usd, where as Nullify is quite a bit more expensive however both are great menus and are pretty undetectable) however there are FREE mod menu's you can use too! a little more risky whoever if you're only doing 50levels you should be fine! try either SubVersion which has an RP Loop, should get you too level 50 in 5mins. or Mikes GTA H4X, which also has an RP boost. I have tested them both for RP a while back and i Never got banned so it should be safe for ya!