My advice go with the standard one, less chance of being abused.
A vtec controller aloows u to change the point the VTEC kicks in, for example if you wanted to inprove fuel econemy you would raise it so you wont be driving around in the vtec. Or if you wanted to have the vtec kick in earlier if you racing ( you should be in vtec anyway so more for starts ) you can set it to be lower. It wont affect power and IMO is a pointless mod but each to there own.
Rpm efficency indicator not sure what that is but this is what google said :-
''In accordance with the present invention, apparatus is provided for determining instant readings of revolutions per minute (r.p.m.) and engine efficiency (ratio of fuel input to engine revolutions) and an averaged reading of r.p.m. and engine efficiency. The apparatus provides electrolytic cells forming a first energy reservoir into which energy is introduced proportional to the r.p.m. of the engine and a second energy reservoir into which energy is introduced proportional to engine efficiency, for a predetermined length of time. The introduced energy is then extracted from the reservoirs while a corresponding registration is obtained, such registration thereby being an average of engine r.p.m. and of engine efficiency under the given operating conditions. ''
Hope this helps
Buy the standar one IMO.