Do I need crush washers or any sealing hardware when I bolt this in?

The fittings come sealed and torqued from the factory. You'll need crush washers when you thread into your block, turbo, or filter block — grab a 4AN crush washer kit if you don't have them. Most guys already have these on hand.

Can I cut or re-fit the line if the length doesn't work for my layout?

This is a hard line with fittings already crimped on both ends. Length is fixed. If you need custom routing, you're better off buying bulk 4AN line and a fitting kit to assemble yourself. Measure twice before ordering.

What's the pressure rating on this line?

Pressure rating not specified in the product data. For turbo and supercharger feed lines on naturally aspirated or mildly boosted engines, 4AN is the standard. If you're running serious boost, verify the burst rating with the supplier before committing to this line.