Wiring multiple gauges into my 240sx HELP!!

[CSXTacy]

hey there guys i am new to this site, i just searched the archives and could not find any answers to my question. i have a 89 240 that i am doing an sr swap on right now. i removed the stock cluster and am running all aftermarket gauges oil pressure,water temp, egt gauge, AF ratio gauge, boost:etc. i am also running a APEXi avcr and Apexi Safc2 finally i am running a auto meter 5inch tach. now the question i have is both apexi units and my autometer tach have a wire for tach reference if i splice this into my tach signal on the ecu will this make any of the gauges inaccurate? will having all these gauges tapped into one ecu wire draw too much current? like i said i searched the archives and could not find any info on this subject. any help would be much appreciated!