why don't you do an engine swap from the 1.6 to the 1.8. If you look at flyinmiata.com they describe how to do it and let you know which parts are interchangeable. You could sell your 1.6 engine on ebay and probably cover the cost.
The other option could be to look at the universal scoop offered by agm to see if that is large enough to cover the 1.6 engine.
I was going to install the 1.6 engine in my car but may now just go for the 1.8
I suppose there is a market for someone who is able to make an adapter for the 1.6. This is my preferred engine (can bolt on a turbocharger later on quite easily).
http://flyinmiata.com/tech/1.8_conversion.php
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Click to see my build photos on Flikr
http://www.flickr.com/photos/67112582@N03/
Saturn MX5 Based Chassis, Limited Slip Diff & 2.4 Quick Rack.
Build cost.... seems to be spending more on tools than car bits at the moment! (they will be handy in the future though).
Car iva'd and passed 15/08/2014. Finished weight 572kg.