oil and carbon build up on the exhaust port....
 

I have a 13b and I recently wanted to swap to a single turbo but found oil residue in the exhaust, turbo manifolds, and spark plugs. Are my Apex seals to blame? If so is it worth it to buy a master rebuild kit or buy a new rotary?

How much oil. I can't see why the sparkplugs should have any on them. I wonder if the oil seals on the rotors aren't to blame.

The spark plugs are mildly covered, as for the exhaust the build up isn't enough to cause the turbines from moving freely but I can't clean the exhaust/manifold without scrapping or maching brushing the oil and carbon build up. Could this be from back flow of the exhaust?

Apex seals won't cause oil buildup, but side seals might. How much smoke does the engine blow when you first start it? Does it ever smoke when you drive at high RPM?

may also be the oil seals

side seals and oil seals are the same thing :)

No they aren't. There are 3 seals between the combustion chamber and oil. The side seals, the oil control rings, and the oil contol o-rings.

We've ran the motor, and as that it's a straight pipe exhaust, there is a little bit of smoke, at high RPMs there isn't a drastic change in the amount of exhuast but I'm still worried if there has been internal damage. Especially as that my motor has 60K Km on it.

Does anyone know if a master rebuild kit is worth it? Or would it be better to just get a new motor?

I also heard that once you crack the engine block open to reseal the engine I have to replace every seal....is that true?

You really won't know what the wear is on the motor until it's cracked open. A master kit will only cover seals, it won't cover if your rotor housing are warn, or the rotor bearings need to be replaced, or side housings needed to be lapped, etc..

The coolant o-rings are basically a one use only application. You don't necessarily need to replace "every" seal. However, if you crack open an engine that is not a fresh rebuild, most likely there is going to be wear on the seals causing lower than ideal compression (which means that should be replaced).

rebuilding is definitely cheaper ~500-700 for new seals. and you never really know what you are getting with a used jspec motor.
but like Mahjik said, if the actual internals are damaged, then a rebuild is going to cost you a lot more.
if you were to get a new motor the safest bet would be to buy a rebuilt one from mazdatrix or atkins, but those are pricey. its really up to you, but I would suggest a rebuild because since your motor is relatively new the chances that the engine internals are damaged is low.

Thanks guys for the info and advice I'll check up on local places for a rebuild.