-At 52k miles, what scheduled maintenence might be upcoming, aside from normal stuff like oil, filters, brakes, etc. I dont have the Owners manual obviously.
1st, before you buy it, take it to a mechanic for an inspection. A few bucks might save you a LOT of headache and money.
The transmission fluid is to be changed at every 30K miles. Feel free to change the engine oil right away, never know when it was last done. But at 60K, put in new tranny fluid, take off the valve cover and inspect the timing belt. The manual states 100K miles, but I have seen them fail at 60K on other cars. Good time to check the brakes, flush the fluid if not looking clear. Oh, plugs take 5 minutes to swap, DIY, keep them OEM with NGK V-Power.
-The car has the 6 disc OEM head unit - Is there a way to do an AUX input adapter to this HU?
This has been done before, in fact There is a how-to for it.
http://protege5.com/vbb230/showthread.php?t=123620193&highlight=amp+stock+head+unit
-What springs will work with the stock struts for the long term?
If you put lowering springs on stock struts, they will wear quicker. I have very limited lowering with my P5, as I have a garage with a steep entrance. I used MP3 springs I got used. Lowered it about .75 inches.
Here is what my car looks like now. Click here.
-Did the leather/6 disc/sunroof package come with ABS and side airbags?
I cannot remember. If you are not sure, the seats will have a tag sewn into them stating side airbags.
-Is this car as easy to work on as the Miata? I like to do all my own work if at all possible.
Heck yeah, plugs are cake, there are how-to's for just about everything. It is a great, reliable car. There are a TON of things you can do to the P5.
Of course, if you boost, you will want to look into internals, as the p5 internals cannot take it.
And without further ado, here is my welcome, not to be outdone by Sir Nuke..
"Welcome to your new addiction! This is the advice I have given for new P5 owners.
Right after I got my P5, I got the intake. You can get a short ram intake (SRI), which is what I have. Others have cold air intakes (CAI) They are about the same on ebay, but you may also opt for name brand. I have the ebay...
The next thing I did was get rid of those god forsaken Dunflop piece of s*** stock tires. I hydroplaned within the first week or so I owned the P5. I ended up with the Yokohama AVS ES 100's. 205-50-16's on the stock rims. After 23000 miles, they were through, so I got aftermarket wheels, and Kumho Ecsta 711 205-40-17s. There are a bazillion threads about tires. These I highly recommend for rainy climates. (Bottom line, get out of the stock tires before you have a problem!)
I just got (after 2.5 years of owning my car) a Racing Beat exhaust. I got an insanely good deal on it. It is on the higher end of the pricing range, but you can score one used at a good rate if you are on the forum within the .245 seconds someone posts it for sale used. They run in the high $400 range new. There is a Mazda Sport (Mazdaspeed) exhaust which is also popular, but people have complained of droning, or an annoying sound at freeway speeds. The Racing Beat does not do that. But there are a bazillion threads about the exhaust subject too, look them up.
Then there is the tinting of windows, a stereo, springs/shocks/body kit, Underdrive Pulleys, carbon fiber everything, etc you will see around here for sale.
Short shifter is next on my list. Kartboy makes a great one, I have seen it in person. The shifter bushings are a must. Get them no matter what. Huge difference in shifting!
I found by moving to synthetic engine and transmission fluids, I get better mileage, and it shifts smoother too. So easy to do, it is worth it.
One more thing you should consider when you mod is a header. OBX and Ractive are the most common. I just installed the Ractive, and love the HP gains. Be sure to look up the Spark Plug non-fouler trick for the 2nd o2 sensor. It prevents the CEL from coming on.
Well, good luck, and check out the for sale section, and work with the Authorized Venders and sellers! Oh, search for threads about a question you might have. Most likely, it has been covered."