You do what you want to do really. I enjoyed having my rotrex'd VR6 but only changed it as there was a lot of welding needed doing underneath and would of cost a lot of cash to get the car sorted how I wanted it to be. Also rings needed doing on mine as it was blowing smoke near the end. I wanted another car and wanted to try a turbo again as id had a R5 GTTurbo when i was 20ish and loved that. So try both IF you can find someone with a rotrex'd VR that is. They are out there trust me