The 86 is currently a hot topic and that can give us an edge at car shows.
At my 1st car show last summer in our state capital, they handed us a scoresheet with judging criteria broken down into engine bay, interior, exterior and criteria I find odd such as model (like an umbrella girl) and decals. I forget if there were other criteria such as stance. But it was a legit production because they reward real trophies, cash, and tour the country. I got lucky and won Best Subaru.
My 2nd show was hosted by a local shop. They didn't keep track of attendees. Some didn't even pay entry and got judged as contestants! They used engine parts welded into odd shapes as trophies and some fell apart as they were handing them out lol.
I think the judges just walked around and looked at the cars, no scoresheet. I lost to a stanced WRX. So maybe some car shows give bias towards stance nowadays? You might want to consider that. Then again, this 2nd show wasn't as legit a production.
I guess be mindful of how legit your car show will be. Mine were all in the Midwest and the scene over here is a mixed bag. I grew up in California; my perception of those shows is they're ALL generally legit. And I'd try to mod according to the criteria I listed in my 1st show.
Edit: They will not give much points for power mods that they cannot see/are hard to notice. Those mods will only help if you participate in their drag race or other demonstrations where power mods make a difference. But when parked for show, you're better off spending your money on mods you can see that stand out visually.