Though I am not an expert in MM or Sales, I have done some initial study of these modules, I have also worked during our training on material classification. I believe you can create classifications for the material. Each classification can be given an ID and description based on the model year. The item pricing can be based on the classification. For each classification you can have different pricing. When selecting an item for a sales order, you can then select which classification you want to have for a line item in the sales order. This will dictate the pricing for the sales invoice line item.
You can use classification for other purposes also. For example, motors of 2hp capacity are slightly different from 3hp ones. So they may have slightly different BOM’s – which would contain a slightly different sub-assembly. Here also you can create a classification for the motor assembly.
Hope this will solve your problem. Good luck.