personally I think chevy nailed it with the gauges so I am using a stock cluster with tach in my truck that has an LS based drivetrain with a 4L60e trans.
for the speedo I have one of these Dakota digital units that gets the reading from the trans and sends it to the speedo via its own cable. the nice thing is its fully adjustable so I can verify its accuracy with gps and adjust it on the go quickly.
http://www.dakotadigital.com/index.c...rod/prd886.htm
for the tach im using this Dakota box that changes the lo volt 4 cyl pulse to a hi volt 8cyl output for the stock tach to read correctly. also able to verify via an OBD2 port monitor.
http://www.dakotadigital.com/index.c...rod/prd127.htm
the only thing im changing out is the ammeter since I have a one wire alt setup. just bought a late model volt meter to retrofit in.