Just a word of caution before you buy a K1 Speed driver, which is the most fantastic driver on the market. Check very carefully that the driver you are purchasing DOES NOT have "K1" embossed in the club face. If it does it will be illegal to use in competitions in the UK as from 1st January 2008.
I give this advice as The Golf Channel/JJB Sports exchanged my illegal K1 Speed for a new legal one free of charge - GREAT TO DO BUSINESS WITH. Illegal K1 Speed's are still being offered for sale on e-Bay so be very careful.
K1 Speed driver with knife technology is the best - my handicap has reduced from 18 to 12 due to purchasing one. Thanks to JJB Sports I have a legal one now !!!!
Happy, Legal Golfing