The International Cessna 170 Association

I made a new one in Excel, glad to share it. I use Foreflight now.

There are apps the can be adapted such as the W&B part of ForeFlight, but none that I know will work well specifically for the 170 as the spreads I created a long long time ago. You can find them here: http://www.cessna170.org/forums/viewtopic.php?f=26&t=10379 Your Link doesn't appear to wo...

It looks like they read your post. The autopilot is listed at $3495 on thestcgroupllc.com

The STC Group looks like a viable option. This clip from AOPA Live, https://youtu.be/sutybAuNaLw explains more.