An excellent post but I'm not sure that it does clear up the issue.
As there is no engine oil cooler installed on the vehicle in stock form, adding an engine oil cooler is clearly not a "replacement part". Further, as the vehicle, from most accounts, does function as intended when used legally on the street, I would think that the addition of an engine oil cooler could be reasonably construed as a modification intended to improve performance (i.e. make the car trackable).
Finally, regardless of the burden of proof (not to discount that important fact), a consumer still has to initiate legal proceedings which is generally not an easy, inexpensive or quick process...even if the consumer ultimately prevails and is reimbursed for any legal expenses, etc, it's still not an easy process.
If I'm missing something critical here please elaborate...again, excellent post IMAHO.
