Hi,
As it is written:
We will update the HikaShop package as soon as possible with that patch.
The patch as been submitted and as far as I can see, the current 2.6.0 is up to date for the patches.
So ; you can simply re-download HikaShop 2.6.0.
About the performances ; I'm sorry but it is really too vague and there is too few information to be able to give you a clear answer.
But for the generic answer ; it will be "no" and could be also the opposite because I personally made some performance patches in the latest releases in order to increase the speed of product listing generation and some other stuff.
Regards,