Oil on spark plugs brand new? Is my engine stuffed?

Did you replace the spark plugs with the same brand recommended by ? Might also what to go over all the wiring harnesses, you disconnected when replacing the exhaust. Might of pinched a wire.

Yeah mate whilst that spark plug is out of the block plug it back into the spark plug lead and earth it to the body(make sure it's touching steel)Turn the key... the car should start but run rough if the spark plug is touching steel but NOT sparking then you have a coil problem.......

For the engine to run, it needs compression, fuel, and spark. having the proper tools for the ob is best but I will go with things readily available, without special tools.
Disconnect a spark plug and put a screw driver in the boot to touch the metal inside, place the shank of the screw driver close to metal, about 1/4 inch and crank the engine and look for a spark.
After cranking the engine, fuel should have got on the spark plug, remove the spark plug and check if it's damp or wet with fuel. Carburated engines are viewable if you operate the throttle and look down the carburator for squirting fuel.
With the spark plug off, stuff a rag on the threads where the spark plug threads into, don't fill the cylinder with the rag, just cover the hole by stuffing a rag on the threaded part, use a screw driver, then crank the engine, the rag should pop out of there during the compression cycle.
Apropiate tools needed is a spark tester, compression tester and fuel pressure tester and noid light. If you have these tools it is prefered you use them.

Nick, I would start with the easiest things first and do a simple elimination until you figure out exactly why it won't start. #1 Spark plugs. #2 Spark plug wires. #3 ignition coils.#4 air/fuel filter. #5 Fuel injectors. #6 Fuel pump. #7 Electronic control module(ECM)/computer. If these things I have stated are replaced with new, then there is no reason it shouldn't start. I gave you this list as easiest to hardest to replace. You may find that the problem is only with the spark plugs, then obviously you have detected the issue and do not need to continue replacing components. I hope this helps, and good luck. ^^

Usually a bad ring or seal inside your engine allowing oil to get into the combustion chamber where the tip of the spark plug is located. Do you notice any smoke coming from the exhaust pipe ?? Do you seem to be adding oil more often ?? If so, the black oily stuff is "engine oil".

Rear main seal on engine it is between engine and transmission .

Remove the spark plug and look at its tip. Most common causes of misfires:

• Burned oil on the tip may be due to faulty rings or valves or just the PCV valve. In such cases the engine will smoke.
• Gas on the tip means not enough power to the plug or a faulty plug (you may get a faulty spark plug even if it's brand new). If not the plug, the ignition system must be checked.

"freeze plugs" actually are installed in a block to seal off the holes where the stuffing that is put into the casting gets removed. The stuffing is what forms the water jackets that cool the engine.
That said, there is no way a freeze plug can ever leak oil because they only cover water passages.
Keep looking and you will find the actual leak source!!

1st check quality oil and filter, if oil and filter is good, then remove engine oil pan , clean oil pump strainer, instal oil pan , add new oil and check.
if have oil on spark plug inside of cylinder, you need to overhaul the engine, if oil is over the spark plug ,change the valve cover gasket

No it is not,have the belts,and pulleys checked,and see if there arte any codes,spark plugs burned to a wider gap,could cause the engine to ping,make sure you are using specified oil,5 w 30