Right guys I'm going to be doing a hpa polar star jack install into a scar soon ( assuming that most the version2 gearboxs are relatively the same across the makes but it will most likely be on a G&G scar L ) just wanted to know any differences in the two gearboxes and external gearbox parts things like trigger unit , selector plate etc , they whole gear box is going to be stripped out anyway apart from trigger unit safety , Spring guide and that's about it off the top of my head ...