I need to find a replacement to this part but I don't know the name of the part or what are its uses.

 

it initially had 4 wires on it (all of which were not present when bought) because there are 4 bulges where there seemed to have had wires of some sort.

 

That's where the reverse, 5th gear, and neutral switches are. I am not sure if you can replace that without taking apart the whole transmission.

 

Thanks for the info, I actually took that thing off with a wrench and found it had a spring loaded pin.

 

oh, and with this part in mind~ I have some mounts that I don't even know were they go and which part of the engine or transmission they connect to?

 

You need to get a copy of the factory shop manual from one of the links in the FAQ. It's free. Also get a copy of the parts fiche from here:
http://www.mazdaspeeddevelopment.com...s/rx7pubs.html

 

those mounts don't look like anything I have seen on either s4 or s5 13Bs. They might be diff mounts but I've never dropped the subframe on either of my sevens so I don't know what they look like

 

Just out of curiosity, what does the 5th gear switch do?

 

tells the ecu that the car is in 5th gear and to turn off the shift up light.

 

It (fifth) tells the ECU to open the split air valve. That valve is located on the ACV.

Fifth and reverse are on the switch on the left side of the transmission. The Neutral switch is on the right side of the transmission.

JDM transmissions have only the reverse inside that switch. They don't use a Split Air solenoid.