Let me preface this by stating that while I am an attorney, I am not licensed in Texas.
That being said, unless the seller has sufficient contacts in the buyer’s state, the buyer’s state will not have jurisdiction over this case. An example would be the seller actively advertising or directly selling in the buyer’s state. A generic ad such as on this forum would be doubtful as to having sufficient contact with the buyer’s state. See:
https://www.supremecourt.gov/DocketPDF/18/18-8515/92742/20190322101738838_00000011.pdf
In this case, the buyer is claiming a fraudulent sale. The buyer just needs an attorney that is well versed in fraudulent sales. No need for an attorney with knowledge of Porsche engines. The case will be judged on evidence of what was advertised and what the product turned out to be.
I think the buyer is going to have a difficult time prevailing in this case. The rationale being that the seller was not the entity that did the engine rebuild. I would imagine the seller’s attorney is going to state that the seller relied on information provided to him by the individual he bought the engine from.
Of course, if the buyer has evidence that the seller performed his own inspection of the engine and stated it was in “like new condition”, that could certainly change the weight of the evidence in this case.