My Chevrolet Lumina SS calls for use of "Heavy Duty Brake Fluid (DOT-4 Plus)".
The brake fluid bottle I have readily available is DOT 4; the label claims to be compatible with DOT 4 and DOT 5.1 systems without mentioning anything about DOT 4+.
Do I lose anything by using plain DOT 4 fluid?
DOT4 has a lower boiling point than DOT4+ -
Regular DOT 4 has a minimum Wet Boiling Point of 165 degrees Celsius, while the DOT 4+ spec is 180 degrees.
according to this website. While you could use water in your system (until it boiled) to stop your car, I wouldn't recommend it. Could you use DOT4? Sure, but you'll be giving up some wet boiling temp to do so ... where you live, this may be of great importance (generally meaning you may need the difference of heat protection due to your climate).
