Toyota Prado 2010 Problems

Check the electrical connections on the horns and also check the fuses.

This is typical of a problem with the Prado blowing engines at high mileage. It was due to carbon buildup on the oil pickup in the sump, the carbon resulting from a leaking fuel-injector seal that allowed fuel into the oil and contaminate it. The dealer's report would suggest that this is not the case, as they appear to have checked the fuel and oil systems for contamination and carbon buildup. You could have an independent mechanic check the engine for you to see if they could find a cause that contradicts the dealer's findings.

It's a common complaint and is related to the injectors Toyota uses. They have been replacing injectors, and that usually fixes the problem in the short term, but the noise comes back once the injectors wear. It's an annoying problem, but it's unlikely to cause anything more serious. If you are concerned about it, take it to a diesel engine specialist. 

Your experience is not uncommon. We had a number of reports from Hilux owners in the year of so after the ute was launched, but we thought the reprogramming of the computer had fixed the issue. Perhaps it hasn't. Talk to your Toyota dealer, and also get the advice of an auto transmission expert about fitting an external oil cooler. If you plan to travel over hilly terrain on your next trip it  would be a good idea to fit an extra cooler.

The dealer is incompetent, and lazy. Contact Toyota’s customer assistance people and report your experience, with the car, and with the dealer, as they need to be hauled over the coals. There is something wrong with your car and, you’re right, it needs to be fixed. If the dealer and Toyota say it can’t be fixed, which I seriously doubt they will, park it on the dealer’s forecourt and ask for your money back.

The problem you have is that deterioration of the finish is regarded as wear and tear, so to get a warranty claim up you need to show that the degradation of the finish on your bulbar is beyond what would be regarded as "fair" wear and tear. To do that you could collect photographs of other vehicles of a similar age that clearly show yours is worse and mount a case based on that evidence.   Ultimately though I reckon you won't be successful. I would recommend you go to a retailer handling truck accessories and get   their advice based on the actual condition of your bar.