I would be tempted to just stay with the 27 wheels (at least for now).
The two modifications I would consider:
+1 Aero levers are the way to go.
You might also want to consider barcons.
As for your frame, a little Testors enamel touchup paint, and some polishing compound, and you are done!
Here's my 1987 Miyata 215 ST (one model down, but a really nice bike, and its in Celeste!). It was an ebay find, earlier this year.