I'm an ex R8 v10 owner so I thought I would add my 2-penneth worth.
When I was looking to buy I compared the v8, v10 and GTR35.
The v10 has much more mid-range grunt and in-gear acceleration and the engine makes a nice exotic noise. In the v8, if you put your foot down at 70-80 in top gear, not a lot happens. You have to drop it down a couple of gears and rev it out. Do the same in the v10 and it will surge forward.
I tried the exhaust mod and it didn't really make much difference to the sound, plus I lost a bit of the low down response so I put it back to standard.
Mine was also a manual and it makes a lovely click-clack noise as you move the lever around the gate. Whether manuals will be worth more further down the road, who knows?
Mine was 100% reliable and the only issue I had was with the tracking and keeping the wheels in alignment. I never really gelled and felt totally confident with the handling, which is why I sold it.
Also, strangely, I never experienced any of the attention at gas stations that others have discussed on here - not that that's why I bought it.
Regarding residuals, I found as with other brands, that there's often a big difference between sticker and what the car actually sells for.
Mine was a 2 year old Audi Approved Used car and when I bought it in Jan 2012 I got about 10% off. I sold it in May 2013 for £58k which was the going rate at the time. The car was in excellent condition for its age and miles and wouldn't have needed any remedial work to the body or wheels.
I haven't really followed the market for R8's since, so unless prices have gone up, I wouldn't be looking to pay more than £55-60k for a nice, genuine, low mileage, 09/10 v10
I know its a bit late (only just come across this thread) but congrats to the OP on speccing up a really nice v10 and I hope you will enjoy it in good health.