Yes, the first R's are much like the newer R's. Obviously there are detail differences in spec but mechanically there will be few differences. There was a bit of fuss about dodgy turbos on some early cars but those would have long since had their hardware fixed under warranty. If you read forums you'd be forgiven for thinking there was a huge plague of defective turbos but in reality I don't think that many failed. Monkeyhanger will be the expert on that subject!
I took mine on a semi regular early morning jaunt at 4am today.
40 mile round trip, dual carriageway mostly, up and down hills and round some good bends, keeping more or less right on the speed limit but with occasional bursts of acceleration to test the 4wd grip off a rolling 2nd gear start as traffic lights changed (no traffic about so easy to play about, it was nice and wet and fairly cold too so a good 4wd test) but only up to speed limits.
26mpg. Not great!
Cruise everywhere at 40 -60 mph and it'll do mid to high thirties but as MH says, hit the gas and it'll drop like a stone.
It's a 300bhp car so it'll drink 300bhp fuel.
I think there was a lot of paranoia about turbos when a few of the early ones went, if I recall rightly, maybe 6 people on the R forum had duff turbos (a few failed spectacularly, causing a lot of damage). When I was due to get my R, someone in the parts department at Benfield said they'd had 4 new engines for Rs with failed turbos causing damage. He said that 3 of them had been ragged to death from day 1 to early failure with less than 2k miles. People do imagine the leased cars getting more stick than the ones bought/PCP'd.
My turbo failed at 4.5k miles, but there was nothing catastrophic about it, it just failed to spin up and work a few times before it was replaced.
Gave my car a bit of ragging halfway home to keep an Audi SQ5 off my back bumper - lots of fun, still ended up with a 32mpg commute.