No, you cannot return the vehicle.
But, I would suggest you can find a local consumer law attorney who will gladly take this matter. What you are describing is a deceptive act under Indiana law:
IC 24-5-0.5-3 Version b Acts constituting deceptive practices:
Sec. 3. (a) The following acts or representations
as to the subject matter of a consumer transaction, made orally, in writing, or by electronic communication
, by a supplier, are deceptive acts:
(1) That such subject of a consumer transaction has sponsorship, approval, performance, characteristics, accessories, uses, or benefits it does not have which the supplier knows or should reasonably know it does not have. (2) That such subject of a consumer transaction is of a particular standard, quality, grade, style, or model, if it is not and if the supplier knows or should reasonably know that it is not.
Two things to note, your state includes electronic transmissions - the web site. Also, you were promised something had a particular quality, standard, etcetera - it did not. That is deceptive and you may recover significant damages if you bring a successful case:
IC 24-5-0.5-4 Version b Actions and proceedings; damages; injunction; civil penalties; offer to cure
Sec. 4. (a) A person relying upon an uncured or incurable deceptive act may bring an action for the damages actually suffered as a consumer as a result of the deceptive act or five hundred dollars ($500), whichever is greater. The court may increase damages for a willful deceptive act in an amount that does not exceed the greater of:
(1) three (3) times the actual damages of the consumer suffering the loss; or
(2) one thousand dollars ($1,000).
AND, attorney fees, that means most lawyers in this work will take the matter on contingency or a pay if recover basis.
Also, if you have the original sticker, save it. There may be other penalties for the auto not including dealer-installed parts.
The dealer is playing with you. Their contract
with Pontiac is their lifeblood and some very good written letters from an attorney to Pontiac asking to be serviced by another dealer and mentioning a possible consumer suit - will get immediate action.