[Deduction]

Just wondering, is there a new function in SA-MP 0.3d to increase the size of objects ingame?

No, Im not talking about MAX_OBJECTS, I mean the actual size of a single object.

[mitchboy]

Then you just need to make custom models, increasing their height and weight isn't an option.

[Vince]

You can only scale objects that are attached to a player, unfortunately.