I don't know that any sensors will need to change, at least not much. Depending on the cost, I am a real fan of the CGR-30, but you may be a little bit of install time ahead if the wiring to the 700 is similar to the 900. Beyond that, the CGR an GI275 may use different sensors than the JPI. However, EI has had some options in the past to wire an adapter harness for your existing engine monitor, reducing the cost and removing any difference in install time. One thing I greatly appreciate with the CGR's is that they fit in a 3" round hole, but don't stick out the side (and often over the edge of another instrument), and the engine data computer is remote. The JPI's have as many as 5 or 6 crowded connectors that plug right into the unit, making it much more complicated to install and remove versus a simple single plug with few wires in it. The JPI installs from the panel side, but you need to tighten it in place from the back. The EI installs from the back, and just screws in like all of your other instruments. Just my experience, YMMV.