I use the panel mount version or the one in Genghis link see the one in my link...new they are around £100...mine is very good but like any compass effected by near by ferrous metal objects.
Mine is in a micro...I checked mine by standing behind it with a good hand held and compare indications...not scientific but quite good.
The one in my link may not be the best...not easy to read...but it is there racing type.
Silva 100P Bulkhead Mounted Steering Compass | eBay
Nick.