G'day ladies and gents, I've noticed a large number of people that are new to GTA modding have had been a bit confused on how to do so correctly without the risk of being flagged online. I in NO way endorse the use of illegal trainers in online and will not guide anyone to doing so. I've seen many people thinking that this guide is showing you how to 'hack' online, This is far from the case. This is a strictly SINGLEPLAYER based guide, Read below.
EDIT : Some of the methods in the guide may be OUTDATED.