They will be different as the laptops are physically different. It's not something that I would worry about though, these laptops are on their 3rd version now so any required improvements will have been made to each chassis.
The only people that can answer that are those that have both and have tested them. Which is likely to be no-one on this forum. Ring up PCS and ask them.
or people who work in pcspecialist and know more detailed stuff we couldn't find anywhere
I believe the point is that they are rarely on the forum to answer queries like this. You are better to get in touch direct.
Hi,
Thank you for your email, I can confirm that the 17.3” chassis do have more component room and an extra fan that will enable your system to stay that little bit cooler in return for the extra weight and size of the chassis.
If you have any other enquiries do not hesitate to contact us.