I just acquired a 2006 C4S coupe. How would I verify if the engine has the x51 package? Is there a sticker with info? Can this be elicited from the VIN? Some other method?

 

You can pay Suncoast $10 to decode your VIN and tell you exactly the options you have.

Or you can take a look for x51 parts. Some of them are awfully hard to install aftermarket, so if you have the parts, it's very likely it was x51 from the factory. Pop the engine cover and look at the airbox - if it is carbon fiber and has a snorkel on the left and another on the right to suck air through the deck lid, you have at least confirmed that you have the x51 airbox. If the airbox is black plastic and only has one snorkel on the left, you definitely do not have x51.

 

Another visual indicator is PSE exhaust. I agree that getting the VIN decoded is only sure way, as anyone can add the air box and PSE, but you can't visually verify polished ports inside the motor etc. But if it lacks PSE and the special airbox, then it definitely isn't X51.

 

I would pay the 10 USD and get it, anytime you resell the car it is helpful
I always keep window stickers on all my cars. It helps with resale.
Does not increase value (although in case of the X51 it very well might), but definitely puts you in the "I care for my car" category.
my 2 cents

 

does the 997 not have the options sticker under the front trunk like the 996 ?

 

Alas! I have a black plastic single snorkel, so I don't have it. Thank you SecretAsianMan for that quick and definitive way to rule it out.

The person I bought from was not the original owner, and I did not get the original sticker with the purchase, but I would dearly love the info. I am a newbie, so could I hear more about Suncoast and their service? Is there a way to get a copy of the original invoice (options and price)?

 

You can't purchase a window sticker however, you can order a certificate of authenticity from Porsche that lists all the options. Cost is around $100.

 

Stopped doing that at the factory on the 997. The sticker exists but dependent on the dealer fixing it to the underside of the hood. Some dealers will attach it to the inside of one of the car books (Warranty??) however most will just leave it loose with all the books and then who knows where it will end up.