Fusionfiend

The platinum series has a proprietary hop up arm with a cut out to take their nub. I found it much easier/better to change the complete hop up assembly to one with better tolerances. I like Maple Leaf hop up rubbers and Omega nubs but I also enjoy crafting my own nubs. It really depends on your FPS limits and ambient temperatures. One of the great things about airsoft is that it doesn't cost a lot (other than in time) to play with different combinations of parts until you find the optimum. As regards barrel compatibility I generally find most things fit with a bit of fettling and/or PTFE tape to ensure a perfect seal.

We have 2 in the family. Both have been upgraded with Aluminium hops, ZCI stainless barrels and Maple Leaf rubbers but home made nubs. Accuracy and consistency improved for relatively little cost. Parts sourced from AK2M4 CYMA 098a Platinum and others in the series are a great value entry to the would of 7.62 DMR (with a version 2.5 gearbox as standard). Haven't changed anything else internally other than to re-shim and check compression (and remove lots of excess grease). Can't see a performance/cost/benefit to upgrading anything else yet.