I finally got fed up with all the issues of the factory GM-Bose on my '90. It sounds good, when it works. By the same token, NOTHING lasts forever. the new technology is cool too.
I had my local Best Buy install a new Pioneer 720 receiver with an Alpine PowerPack Amp and four 6" JBL co-axial speakers. I "helped" the installer since I knew a lot of the cars anatomy. I highly recommend Best Buy. My local one had a real good installer. In fact he is the manager of the installation dept., so I was comfortable with him. After talking with him prior to the job, I knew he knew his stuff. The trick is to find someone who has done Corvette's. He adapted the factory speaker enclosures to accept the 6" JBLs'. The fronts are challenging since they come with a 4". The 6" WILL fit with slight mods. I had also printed the appropriate pages from the FSM for the radio head power connections and the antenna control. We left the old Bose amp buried in my dash(I believe the '93 has it in the storage compartment).
First off you will want to take out the seats, console top and dash panel, then the right side kick-bolster.
My system is awesome and I love it. Plus the Bluetooth capabilities of the new stereos is amazing. We drilled a small hole in the radio dash panel and mounted the microphone there. Plus with a USB plug I have all my favorite music on a thumb drive or play it off of your phone. Works like a charm!!
Best Buy also has 12 month "same as cash" financing. Good Luck!