Thinking about installing a battery kill switch for a parasitic drain — good idea?

Long story short: 2008 Infiniti G35 I bought at auction has a parasitic battery drain (mechanic checked all fuses, thinks it’s aftermarket wiring). Battery dies if the car sits 24–48 hours. Before I throw money at tracing/rewiring, I’m considering installing a simple battery kill switch or disconnect to prevent the battery from draining when parked.

Has anyone used a kill switch or inline battery disconnect as a stopgap? Pros/cons I’m thinking of: stops the drain, cheap and fast; cons — inconvenient daily use, may reset electronics/ECU, could interfere with alarm/immobilizer or stereo memory. Any tips on type (rotary vs. lever vs. Smart Battery Disconnect) and where to install it? Should I have a shop install it or doable as a DIY? Appreciate real-world experiences.