Hello.
It's almost impossible to say if any RX-8 is good or bad by just looking at pictures and reading description. Take it for a test drive , check if the rpm is stable , check if there is any lack of power or any mysterious noises from the engine. If you are in doubt about the condition of the engine you can always get a compression test performed which will confirm the condition of the engine.
So instead of judging a car from pictures , description etc go and check it.
Although not many good RX-8s' left in pakistan now , most are treated like everyday cars and then the owners face engine issues and swap some JZ or other series engine. I would never replace the Rotary with any other engine , cutting the engine bay for more space , cutting the firewall for more space so the transmission can get in ... etc. All these things make me sick.
My plan is to make mine more powerfull by modifications recommended for the Rotary , not by swapping an engine which is 3 times more heavy and then doing alterations to the car , this way your car can never stay out of the workshop and it is just extra headache for the owner. If your Rotary starts giving problems , rebuild it ....easy as pie.
Do some research about maintanence and etc about the RX-8 and its engine before buying one , lot of usefull posts one page 1 , check them and after that check wikipedia or something.
What car are you having now or used to have?
Thanks.
Bye.