Swivel seat base — which brand fits a Sprinter 2015+?

Want to add a swivel base to my driver's seat in a 2018 Sprinter. I've seen Kiravans, Scopema, and some cheaper eBay options. The Kiravans one seems popular but it's about £250. Does anyone know if the cheaper alternatives are any good? Also, how much height does it add? I'm 6'2" and already quite close to the ceiling. Don't want to end up hunched over!