The issue of altered sensory processing for persons with autism is a comparatively new line of research. I found a couple of articles connecting it with classic IQ assessments, and one that deals with changes in sensory processing in school children, but nothing clear to your topic. You are looking at a wide open topic for research.
These articles will be useful. Yes it it a very understudied area. I have found some work on educational outcomes by Jill Ashburner and colleagues and one looking at participation in school activities that I have added below.
Dear Aislinn and Julia, I will add them too. I am worry about the new pathology "sensory processing disorders", The relationship between SPD and Autism is an area of great interest to scientists and families living with the condition. Studies by the SPD Foundation suggest that more than three-quarters of children with autistic spectrum disorders have significant symptoms of Sensory Processing Disorder. However, the reverse is not true. Most children with SPD do not have an autistic spectrum disorder! Some research suggests that the two conditions are distinct disorders just as SPD and ADHD are different disorders. What do you think about it?
Very useful articles, I would also add them to my collection. Dear Aislinn, I think that it might be useful to read the Mayer, Hannent & Heaton (2015) paper (http://link.springer.com/article/10.1007%2Fs10803-014-2207-6) in which they reported evidence about the relationship between auditory sensory processing skills and communicative ability and perhaps our paper (link: http://link.springer.com/article/10.1007%2Fs10803-014-2219-2) that reports evidence about the relationship between enhanced auditory perception and IQ (check also citations). Both papers are available on researchgate. I wish you all the best with your research project.
"The issue of altered sensory processing for persons with autism is a comparatively new line of research"
I recently raised the matter of the omission of sensory disorders with a distinguished clinician involved in old DSM diagnoses of autism. One point he conceded was that anyone who had come up with a proposal to study sensory disorders in autism would not have got the grant since these were not in DSM! This situation should slowly be rectified now that sensory disorders are in DSM 5.
By far the best information about sensory disorders and their central relevance comes from the autobiographies of grown-up autistic persons.