No, not really, I had a Horizon electric tach in my Comanche before I went full engine monitor. It worked perfectly and fit in the same hole as the mechanical tach. It appears the company may have retired since the product is no longer listed on Aircraft Spruce and Specialty. But there is a used one on eBay: type Horizon P-1000 into the eBay search window. Asking $250.
There are a number of approved replacements. A couple include the Electronics International has its R-1 and the J.P. Instruments Slim Line tach.
If you haven’t yet decided, you can get a TruTrak II from Aircraft Spruce. This is a portable battery powered unit that is not connected to any aircraft systems. Velcro it to the dash, point it at the prop (it can adjust for 2,3,4, and 5 bladed props) and get a true reading of your engine rpm.
