You can use the Fitment Buckets that come with the app for niche sites instead of a YMM search- for no extra charge! Having one or more fitment buckets makes it easy for your buyers to shop using their mobile phones. They can quickly select from whole groups of items. This is different from a classic year-make-model (YMM) organization of categories where your customer would have to go through and select the specific items one by one, which is done more easily from a desktop.
This link will walk you through how to create a Bucket.