https://eagle6.co.uk/shop/catalog/product/view/id/2095/s/laylax-nineball-g18c-custom-slide-eckesachs-for-g18c-gbb-series/
Only slide I managed to find having a quick look. Stock marui ones seems to be out of stock everywhere. Maybe worth emailing eagle6 or impulse101 to see if a restock is due?