If youre looking to build a new bike for the summer or upgrade your current one, a quality groupset is a great investment. Shimanos excellent 105 Di2 has near Dura-Ace and Ultegra levels of performance, and it currently has up to 54% off depending on where you buy it. It features most of the same features as its older siblings, although it's 373g heavier than Ultegra and doesnt have a third button on top of the levers. When it launched, at 1,730, we gave the groupset a 4-star rating, concluding it was likely all the groupset any amateur would ever need. The groupset is 12-speed and is the latest R7170 model. Russell Burton / Our Media Weve found three retailers Sigma Sports, Certini and Winstanleys Bikes offering the groupset for 799, while Merlin Cycles is selling it for 825. At this price, its seriously worth considering if you're yet to upgrade to electronic shifting. There are plenty of options still available. Ashley Quinlan / Our Media Across the retailers, theres plenty of choice of crank lengths, chainrings and cassette size, so there should be something for every bike. The 105 Di2 derailleur is very neat. Ashley Quinlan / Our Media Crank lengths start from 165mm to 175mm, the chainrings are 52/36t or 50/34t, and the cassettes are 11/36t and 11/34t. Here are the links to the retailers, so you can vote with your wallet and pledge allegiance to whichever one you please. Buy Shimano 105 Di2 from Sigma Sports for 799 Buy Shimano 105 Di2 from Certini for 799 Buy Shimano 105 Di2 from Winstanleys Bikes for 799 Buy Shimano 105 Di2 from Merlin Cycles for 825