Shopify has a limit of 250 tags per product. Basically, our app just connects search term combinations (particular year/make/model) with certain URLs. It may be any URL - tags, collections, search, or even 3rd party website. By default, we recommend tags as that's native and the easiest way to use the app. Also, our helper tools like Visual Database Editor also tag your products in the background - so still using tags. But if tags don't work for you due to that 250 tag limitation, you may use collections instead (but of course, it will take more time to set up), or a combination of tags and collection.
EasySearch - FAQ