celica are run with chains,
spark plug are all the same not much difference, TRD
makes LSD for celica and also you can't really compare LSD they are all the same. TRD
makes pistons for 2zz only in japan, and brashboy, trial makes stroker kit.
Just an advice, the celica parts are almost same, there isn't BEST parts for celica. The difference between parts are quality and sound, and characteristic. So you can't really say BEST to any parts. Also Its very hard to find celica parts. only good parts are available in japan. Go grab yourself HYPER_MAG celica editon in little tokyo or japanese book store. And they have almost every parts list and detailed information on celica parts from Japan.