If you boost the legal items, the same thing is going to happen, any item that is worth the time and effort to make a large profit, will be sought out by all, especially larger gangs. All you would achieve is a shift from mass illegal camping/robbing to mass illegal and legal camping/robbing. The gangs that give you a hard time have the numbers to lock down both. By keeping legal items at a lower price, it allow's larger gangs to focus on the most profitable, being illegal, and they only prey on legal items if a "target of opportunity" presents its self in most cases. In addition to keeping the larger gangs running illegal items as they are at a higher price, it also forces them to deal with APD and other larger rival gangs, which should in return divide their concentration and in theory keep them limited to preying on legal zones.
This is not always the case however you can never really ever expect to have easy street on any profit making ventures in Altis Life, that's just how the game mechanics work. Even while running legal items you have to be smart and cautious on how you operate. Here is a simple set of "guidelines" that can help your venture.
1. do not set a pattern
2. run with 3 or more members if you plan on doing a big run
3. steer clear of large transports, tempest devices and heli's (like a huron)
4. pick times/routes that will help to conceal your operation
5. Buy a house in the middle of gather/processor or near a processor and do not try to gather/process during the same run
6. Have a lookout and keep an eye on market prices
7. Watch for chatter to get an insight to what other gangs are doing and try to work around them.
8. Create diversions by pushing "misinformation" to mislead other gangs into thinking you are in an area other than that of which you are
9. and finally, RP RP RP, if a gang runs up on you, and you have great RP (that is if they don't merk you on the spot) they will usually only take a few items from you and let you live if you don't immediately get all butt hurt and start bitching or acting like a 5 year old brat who is whining and crying.
Most people will respond positively to great RP, you may not get off scott free, and may not even get away with you life, however your chances are waaaay better if you do.