The turn signal relay is located under the driver side dashboard above the fuse block mounted to the kick panel.
stock springs
The 1993 Honda accord, I believe, does NOT have CD Player. It only have cassette and radio player.
6.5 fron and rear
http://www.installdr.com/InstallDocs/Honda/PDF/466053.pdf
Whatever Honda could get cheapest when they ran out and had to order more.
150 at 5,700 rpm
Try this: http://mjmautoinnovations.com/honda.htm
6.5" front and back
not much around 120
Front and Rear 6.5 Inch
A common problem for many stock radio is a blown fuse. Find the fuse in the cabin of the Honda Accord and check it's connections to see if it is not burned.
Assuming we're comparing top trims on either car, and we're also talking the Accord coupe (not the sedan), the Accord would best the Supra by about a second from 0-60.