In plain text from source (scanned original email)
Dear Heng
My Opel Vectra, which I DIY fitted from one Surbo to a Twin Surbo following your instructions, gave me better result on the fuel. With one Surbo my FC was 9.8 km per litre, and with the Twin, I am now getting 10.6 km per litre. I am happy with the result.
Thank you
Wong
Singapore