I really doubt mate that someone is gonna rent the personal car like this. You can check plenty of rent a car in Deira opposite arabian automobiles offering all Lexus models. Easier, no obligation and tension free than requesting from individual owner.
the starter of your car is mounted to the firewall in the center under the intake manifold. but if you have never done this before then dont initiate changing it yourself as you may damage more then you have bargained for.
All you need to buy updated maps CD from Al futtaim, same i have done last year. Nothing after that.
If you men after market one, then they shud be installing it for you. Isn't?
Tires are usually change after 3 years or 40k kms - 70k km as per tire manufacturer spec. You can change brand as well, but make sure to keep it same size as OEM specs.
My suggestion for good brand is Pirelli, but expensive.