Yak 18T is a 4 seat tourer with earo. capability as it is a development of the Yak 52. As far as I know, Yak engins are limited to 750h and than £13k or so for a new engine. The same with a Yak 52.
For a tourer I would go for a Piper Comanche. Very fast easy to fly (but make sure to have a very good conversion) and not expancive to keep.