Optics & slides

[ElliottD]

currently I have one project on the go, a m4 block 2 type ar ( apologise if it's defined wrong ) but I'm looking to get a optic for it. I'm stuck between a eotech style dot sight or a spectre Dr style 1-4x optic, which I'm finding hard to get hold of a good one. So which would be best option and what brand would you recommend.
Problem two is I am about to start a new project, a pistol a Tokyo Marui g17, and I wanted a salient arms slide for it. I was wondering if there's any out there that are similar as the SaI ones are becoming harder to find