I have been doing some touring on the Busa over the last couple of monthes and have been getting great economy from the big girl, around 20.5 km/litre(58mpg), just cruising thru our backroads at about 110-120k/ph(70-75 mph).....Last week I removed th TRE as i was getting jerkiness down low in the rev range so thought that may help....Some of the jerkiness has gone but fuel economy is now down to 16-17 km/litre (45-48mpg). First tank full I though Id stuffed up so have run 2 more tanks full thru her and I really struggle to get economy over 17....So last night I plugged the TRE back in and took the missus out for a cruise and well bugger me, economy back up to over 20 km/litre(58mpg) again....Blew me away. I.d never have thought the fuel mapping was leaner in 5th than 6th but who knows what Suzuki engineers think.. Just found it interesting.....