Ohh, I did not know that the Retevis RT97S is Part 95 Certified! I have the (older) RT97 (non-S version) and have had great results with just a mag-mount antenna on the top of my car. You can see how that went in this video:
and you can see how well it works in hilly areas in this video:
I agree with @WROZ250's warning about the Bridgecom - I have not used one, but have read many bad/negative reviews on them (although did not know they had a Part 95 repeater).
I have also built a repeater from two KG-1000Gs - and although it was a great learning experience, its very expensive and not a practical solution for a 'real' repeater.
