I have a 2004 RX8 with 54000 miles on it..I have owned it for 4 yrs and I still love it!!!! Only major problem is starting when too warm or too cold. If I get a new starter motor fitted to the car will this help the problem???
Any one have the answer!!!!!

 

04's did have weak starters.

Hard warm starts are usually low compression, but you mentioned hard cold starts as well, so I would say........yes, it will help and that you don't have low compression(at least not from what you wrote). There is an updated starter for the 04's and you can get one at www.Mazmart.com perhaps.
If you do some searches you will find out the two part numbers and you can verify you have the older one before going down that path.

 

Look at pages 7 and 8 of the attached, then go consult this thread perhaps. https://www.rx8club.com/series-i-do-yourself-forum-73/diy-starter-change-swap-dummies-189410/

 

Rotaries need a strong battery and starter in order to turn fast enough to generate good cranking compression and fire quickly.

The 04-early 05 starter was known to be weak even when new. As the engine wears down some and compression slowly drops, starting issues become more evident even though starter performance hasn't really changed.

The updated 05.5+ starter can help with starting difficulties when paired with a strong battery.

Even so it may or may not fully mask the issues caused by a weak compression engine, and at some point hot starting issues will return when compression drops below a certain threshold.

So the answer is, try the updated N3Z1 starter, and maybe a new battery or one with more CCA. Also tune up the ignition with plugs, wires, and coils if not done so already.

From that point on, weak engine compression will be the most likely culprit in difficulty starting.

 

I forgot to mention the possible weak battery as a potential culprit or hindrance as well.
I also didn't go into the rest either.....so thanks for taking the time!

I need to do mo betta.

 

Although all that is said above is true, I had another problem. I was having problems with slow starter revolutions caused by low amperage to the starter. We replaced the battery, which didn't help. As this was not the original starter, it was an upgraded starter, and it was not very old, I refused to believe that the starter was bad. It turned out to be corrosion on the in the terminal on the starter from the battery. It is low enough in the car to get a fair amount of road debris and such on it. One thing you might want to do is just clean up the terminals and see how it turns. It's free.

 

Yeah, that's been the case before many times as well. Fortgot to mention that as well! Argh!
So much to remember to tell people and you try to first hit the highlights as not to swamp them with info, and you make the assumptions that some things are a given.....................when you really shouldn't do so. Some people(not saying you OP), don't have the first clue about cars in general.