The Golf GTI uses the new EA888 engine while the Audi S3, Golf R and Scirocco R all use the older EA113 unit. The newer EA888 engine is a much more efficient unit and has a metal cam belt as opposed to the rubber one of the EA113. The S3's engine is a proven unit that is both reliable and powerful. in truth, there is very little to choose between the two engines apart from output. Volkswagen/ Audi is simply brilliant at turbocharging small engines. The extraordinary durability of such engines despite the increased stresses they must endure to deliver significantly greater horsepower is a testament to the VAG's expertise in this area. No one can really say how good or bad the new Golf R will be yet, but given the fantastic write up the 'Roc R has received, i fully expect it get rave reviews too.
A lot of people are annoyed because the Golf R effectively makes you pay more for less, since it no longer has a VR6 engine. As someone who owned an original VR6 - and loved it, by the way - fuel usage was savage when you kept your foot down. Fuel consumption is still the big problem with today's generation of V8 supersaloons. So IMHO VW was right to make a car that was more frugal as well as more powerful. Personally, i would have loved to see the TT-RS's 5-cylinder engine in the Golf R. That motor is a beast. With something approaching 400 bhp possible, it would M3s for breakfast.
In the meantime, there is an interesting rumour that VW has been very conservative with the Golf R's acceleration figures. While 0-60 in 5.7 seconds is reportedly possible (5.5 seconds with DSG),
apparently it is nearer 5 seconds.

Of course, if the R does prove to be all hype and no substance, we have the GTI to fall back on. I think the GTI is a stunning motor. The R is going to have to be very good to command the significantly higher price VW is asking for it. I suspect VW realises this, so I'm waiting with great excitement.