You must locate the Performance struct within the specific Car Object and overwrite the stock values with Junkman values.
// 4. Apply Junkman Parts // Note: In NFSMW, parts are often stored as a collection of attributes. // You must find the 'PartID' attribute and the 'UpgradeLevel' attribute.
I benchmarked a standard "Pro" full-tune Lamborghini Gallardo against a "Junkman Top" Gallardo using the editor. The results are staggering: