Don't rush off to the vet in the absence of other symptoms. As PP has said, snakes often make odd and unexpected noises, especially if stressed or being handled. Handling causes stress, due to unwanted exertion (snakes are very lazy animals with very economical energy budgets), which increases respiration, which can in turn lead to sometimes explosive breathing noises. If the animal is otherwise behaving normally, and especially if it is feeding, it does not have RI.
The breeder is correct with regard to lower night temps or even no heating, but your night temps sounds fine - these snakes are nocturnal, and are fully active at temps in the mid twenties at night. I reckon PP is also on the money with raising the day temps to 32-33C.
There are some here who ALWAYS think the worst - that any unexpected noise is indicative of RI and will tell you to rush off to the vets immediately. In the absence of other symptoms - snotty nose, consistent lack of appetite, unusual coiling for example, making the odd puffing or squeaking noise while breathing when stressed is not an indication of RI.
Jamie