Purpose of the cables is to keep brush from running up the windshield and lodging between the roof and the rack.
The rack is a Safety Devices expedition rack and have not been available for years. www.roverracks.com
builds decent knock offs but the mounts are not nearly as stout. Keep an eye out on ebay and craigslist for one. There are versions for the D1 and D2 and the lengths are different so be aware of that. There are also low and high versions. Low ones require removal of the factory roof bars and sunroofs can not open if you have them. High versions allow the roofs to open and roof bars to stay in place.
Snorkel is made by Mantec and a great piece of kit. I thought about making one, but it is more involved than just bending tubing. They look factory and better than the plastic ones that look tacked on and run down the length of the fender.
The sandtrack was surplus UK military from WWII and comes in ten foot sections. It was a group buy with Northwest Overland Society and we got a pallet of them cut in halves. I added cross bars on the rack for the tent, strap steel bent out and then in like the Camel racks to mount the track on the sides and then more strap steel across the front for the dual jerry can holders to mount to. Top it with chicken coop flooring from www.farmtec.com
and you're ready to go. I also added light tabs on the bottom of the lower rear hoop on the rack to mount Freelander Safari 3000 lights so they would mount low enough to clear the tent opening. Home Depot has excellent mild steel square tabs with a 1/2" hole in the center for this purpose. Nothing is easy, but to get it set up right is worth it. You can modify a Jeep spare tire hilift carrier too that goes through the center of your spare wheel... Flip the spare carrier upside down so you can clear your bumper with the oversize tire. Full Southdown skid plates... It never ends.... Word to the wise, I had to modify every skidplate to fit... I would use someone else's skid plates. They are probably the toughest out there, but the design is far from accurate. Gas tank and front axle guard are the only ones that fit right (sort of) out of the box. Steering guard holes did not line up and had to be re-drilled and then notched for the ARB mounts. Rear diff cover bracket had interferance issues with the panhard bar mount hitting it and needed bending to fit the diff right to begin with. Wheels are off a P38 RR and the only 16" wheels I could find at the time....This one is a SE7 so had the worthless 18" Hurricanes on it. Now they have mud tires for this size, but didn't at the time I did this. I like to have sidewall anyway so it is just as well.
Curious about your head unit. This one has HK/Nav but I'd rather have an in dash changer than deal with the magazine under the seat crap. I have yet to hear of anyone having a successful stereo upgrade on these since everything works together. They either have amp/speaker or changer issues trying to change just one component of the system. I'd like to upgrade the stereo in my 98 LSE but haven't due to these reasons.