Yup... Wala naman mura when it comes to "upgrading" a car...
As what you have said in an earlier post, it is much better to just buy a more powerful and quicker car in the first place than having to buy a less capable car and spend too much in modding it but with no guarantee in output gains.
If purely for City driving then get the Emax7. since you already have other cars for longer drives....
BYD Sealion 6 DM-i