He may have a nasal polyp which will cause the noisy breathing. He should be starting his routine vaccinations now, so you might ask the vet about the breathing problem when you take him in for his initial shots. Polyps are usually easily removed with an instrument they simply snip them off after anesthetising the kitten lightly. If you wait another week or 2 your vet can probably take care of the problem and neuter your kitten at the same time. If it is a long standing upper respiratory issue, he will need to be cleared up before they can do vaccinations. A round of amoxicillin or clavamox can probably take care of it if a polyp is not the problem.
Please let me know if I can help further. You might also check your local phone book to see if there are any feline practioners in your area. Cats are ALL they deal with and are used to seeing unusual things that other vets are not, and they are usually no more expensive than a regular small animal vet.