What you have is a 13b 6 port motor, the turbo motors are 13bt 4 port's for that gen RX7. You can turbo the 6 port it has been done many times, the turbo swap is just easy & no real fab work. You can find TII trannys fairly cheap, but you will need the rest of the drivetrain ( rear end, axels & shaft ect ). As far as porting yes you can. There is a few different types of port jobs, some shops have thier own signature port jobs as well. The basic types are Street, Bridge, Half bridge, Peripheral. Check this link for a description.
http://www.mazdarotary.net/porting.htm
The RB headers are the best bet, but if you want to go cheap the Pacesetter will work fine. The N1 exh are nice systems, I don't have any experience first hand on the HKS Hi power though.
Remember when modding a car do things equally, meaning don't just tackle engine componets. Make sure you give the other aspects the proper attention. Making power without traction or control may prove to be a bad decision. Good luck & welcome to the forum, coming from another new member.