We have created header for you using the header builder. Check, please. Search by SKU works with a full SKU number http://prntscr.com/qf4lg9 and partial.
To speed up the search and your site:
1) Disable all the plugins that you don’t use. Every additional plugin slows down the site.
2) Use cache plugin (we installed W# total cache but you can choose any other you like)
3) Reduce the server response time
4) Make sure that DB structure is optimized.
