Keeping my 2017 K5 vs. switching to a 2017 K7

I am currently driving a 2017 K5 LPG.
I'm told I can get about 7 million won if I sell it.
However,
I found that a 2017 K7 LPG is available for purchase for about 7.5 to 8 million won.
I know there will be additional costs like acquisition tax and transfer fees.
Since it's LPG, I don't think the fuel costs will differ by more than 50,000 won per month...
Should I switch cars?