What about using the SL30 plus a GNS 400W? The 400W is considerably less cost than the 430W so it might make sense if you already have the SL30. That is my situation and the direction I will probably go to enable IFR training.
Can anybody share reasons not to go this route for best bang for the buck if you already have the SL30?
I can share reasons why I did exactly that.
The builder of my -7 had a major brain malfunction when he chose to combine dual G3X screens only with an SL30. In today's environment, which both in the cockpit and outside is changing at the speed of light, not to include precision GPS approach capability if you are going to fly in, or over, or under IMC weather is a fool's errand.
We have marvelous aids for enhancing situational awareness, which should allow a VFR-only pilot to remain well clear of IMC, and a marginally experienced/current IFR pilot to avoid the necessity of shooting an approach to IFR/LIFR conditions.
But my approach centered on "What if?" I wanted the limiting factor to be the approaches available within whatever range limitation exists at the time, not a limitation I'd created that flew along with me no matter where I went.
At the time, Garmin had reduced prices on the 400W, which I think was about $4K less than a 430W. It had all that I needed, and since budget was a factor, I chose that option.
The only consequence of that decision I didn't realize at the time has to do with shooting an ILS approach, which like one of the replies suggested, is never my first choice if an available and suitable GPS approach exists.
I'm still working out the procedures I need to deal with this, but the short version is that the User's Guide for the 400w series assumes a 430W. With the GPS and LOC capability included in the same unit, you can navigate using the GPS until the unit automatically switches the CDI source to LOC for intercepting the final approach course. But with the LOC signal contained in a separate unit, this auto-switching isn't available.
Imagine my surprise a few weeks ago when on a practice ILS approach in VFR conditions I activated the approach on the 400W and GPS guidance on the G3X disappeared. There may be a procedural fix for this, but I mention it only to address one consequence of having GPS and LOC navigation info in separate units.
Tosh