Anyone's cats make these noises when breathing?

I have a Siberian kitten, about 5 months old now. I noticed a month ago that he was making some noises when he was breathing. Mostly on the inhale. They are very quiet not like hacking or coughing. I also noticed what looked like very shallow breaths and some rapid breathing. It has never gone above 50, but from what I read 30-35 is more the norm. So I took him to the vet

$65 -vist

$200 - for 2 x rays

$125 - for radiologist to read x rays. 

Vet says everything looks good except she sees some slight inflammation in the lungs. 

Radiologist comes back and says lungs are inflamed and heart is enlarged. 

Main Vet recommends a echo for $750

Go to new Vet, that Vet looks at the x rays and reads the radiologist report and agrees with it and says get an echo, her guy only charges $400

Meanwhile I send the x rays to a friend whos a vet a couple states away. He tells me he sees no enlargement of the heart, that this is a big cat, and very minor lung inflammation, and to not worry about it if hes playing and eating and everything else seems good. Now mind you he is the only one without any financial motivation

Even though I am taking care of the kitten its technically my sisters/dads cat. They want me to do the Echo. 

We do the Echo for $400 and it comes back the heart is a perfectly normal kitten heart, just like my friend said. 

As far as the breathing and the slight lung inflammation I'm at a loss. He seems so happy and playful. Eats a ton of food. 

My dad spoke to a Vet friend of his and he told him that this breed can have a S shaped airway that can make breathing an issue. I haven't found one mention of that anywhere on the internet. 

Here is a link to 4 videos, 2 are only audio.  The cat makes this sound when he sleeps and when away. Not all the time but alot of the time. Its my first cat so I'm trying to find out if anyone else experiences this? 2nd Vet said this is not normal at all. Might be a little hard to hear without headphones or loud speakers

https://goo.gl/photos/oxL9Cdo67DVRGaEx6

thanks in advance

Jay

I'm sorry no one has answered yo yet. I've done some research into Siberians and I've never heard anything about the S-shaped airway. :dk: I hope someone will come along soon with more answers for you.

My Bertha makes a similar noise when she sleeps - I'd almost describe it as snoring - and has done since we first met.  In fact, I can hear her now in her bed behind me.

She's a perfectly healthy 11-year-old strictly indoor cat with a bit of a weight problem. But she sleeps soundly, enjoys playing with her step-brother, and eats well. I think she's very happy and am not particularly worried about her breathing. It could be the same for your little guy.