As Mafs pointed out, it is interesting how the most solid idea to support criminal RP has come from a cop.  Seems that putting thought in to solutions is much better as just shouting you need to get something.

Regarding the HQ, there is a slightly different proposal we are thinking of for RS5.

First of all the problem with the idea. We are basicly against giving advantages to experienced players over new ones. In fact we feeld that players who are playing longer should basicly get a disadvantage, as they have experience in many matters.
There for to give special powers and possibilities to "elite" groups is actually counter productive.

That does not mean the HQ and money idea is dismissed completely, just I would like to see a slightly different system.

Here we go.

Weapons in Ammunation will be the same price for all. To give criminals the possibility to deal (cheaper?) weapons, there will indeed be something like a reverse drug export, where they can obtain certain weapons at a low price.
This will be open for all groups who have a HQ.

What we are looking for is a way to allow mafia and gangs to have a fight, without it resorting in constant and pointless killing. The validation system is, as Panda has admitted, a crutch rather than a solution.

For RS5 we are looking to implement the colour coding. All over SA a number of "Landmark" buildings will be set, each building will give control over a region.
Official groups can receive a colour, which means that for every building they control an area will be coloured on the map. Other groups can still control the area, however without a colour.
Each group that holds a landmark is eligible for importing weapons and exporting drugs. Groups who wish to expand their area or new groups can flag a landmark for posession. If there is no group hodling it, and within two days there is no other group flagging they will get the landmark. If a group is holding the landmark, they have two days to accept or deny. However a group can not deny a flag more than five times.
If the flag is accepted, at a chosen time the groups wil fight for the landmark, in a closed area without interference. There can be different styles of fight, chosen by the group that holds the landmark. The winner gets the landmark.

In the landmakr buildings weapons and skins can be stored, and possibly they will be able to hold vehicles. However if the landmark is lost for the group, so are all things stored there.

What does this give ? First of all the strong groups will get the best landmarks. A group can have more than one landmark, to show they have a large area under control. Gang wars will have actual meaning, as by losing a gang war a group can really lose something, even more than just a boulding or turf.

Also there will be the possibility for FBI and SWAT to flag a landmark, and clean criminals from the city. However in such a fight they will too have to work under gang war rules only, it will not be possible to use normal police tactics.

Something to be discussed is if official groups will get an "untouchable" HQ or not.

By implementing this system random killings between groups could go down, as a group killing others randomly would be "cleaned out" by the police, losing their ability to take part in the criminal scripts.