Why would they be unhappy? It may well come with some nice 4 pot brakes, more power, bigger intercooler, lighter wheels, better suspension, a diff etc over the Cupra.
It would be useful if they told us the spec of the Cupra and the Cupra R so that people who might be interested could make a decision one way or another, especially with the Focus RS, Golf R20T and forthcoming MeganeSport coming out not to mention the all new Vauxhall Ashtray and its VXR variant.
Makes you wonder if the Cupra will be developed any further as the S3 is likely to stay the same, and if the RS3 goes into production it will get the 2.5 lump from the TT-RS.
The S3 won't be allowed to tread on the toes of the TT-S so will stay at 261PS under the 272 TT-S. I'd be surprised, but pleasantly surprised if they allowed SEAT to uprate the Cupra to Cupra R as then it forces the Audi / VW engineers to have to rework their stock to better spec.
With how far the GTI parts bin has been stretched for the S3/Ed30/Cupra, I'm not so sure the VAG technical guys will be inclined to push the running gear / engine / ancillaries any harder (DMF & fuelling issues already). Also if they LSD'd the Cupra and put new brakes on it means sourcing low volume non standardised parts which goes against the cost saving that VAG are currently trying to manage.
I'd love to see another Cupra R, but to be honest the press are touting a new RS3 and that's still marginal to see light of day. There is next to no news on a Cupra R so I wouldn't bet on one at this stage unless the competition are seen to be selling high volumes of new high end models. If it is only going to sell in small volumes given the hard times SEAT won't see it as worth the investment for niche potential.