[Vic55]

Its an apples and oranges comparo... I had a v10 R tronic (2012) modified with exhaust and some other software goodies. It sounded good but the transmission was terrible and laborious unless one was ripping it at all times. SMG's are just brutal in cruising modes IMHO. I now have a 2017 Gen 2 V10 tuned past a V10 plus and its modded with exhaust as well. What can I say, its an amazing car and normal aspiration is just a dying breed as we get over 600 hp.

But I cant really find a way to truly compare them as they both do things differently from a drive feel, chassis response, handling, awd connection, exhaust, and of course engine. But they get to the same place pretty damn quick. The F90 will be faster than your 15 IMHO and off the line it would be close but the F90 puts up crazy launch numbers.

I guess Id sum up my ownership thoughts this way (F90 vs Gen 1):

Looks- to the Audi, its a daily exotic driver but still catches alot of eyes
Sound- to the Audi with its normally aspirated V10
Handling- to the Audi but of course as the weight of the car and the mag ride are hard to beat. But dont get me wrong, the M5 is amazing for a sedan and will impress you around the track; heck it might even be faster than the gen 1 v10 plus in certain areas where there are less turns.
Steering- tough one but the Quattro in the Gen 1 carries a bit of understeer that was greatly improved in the Gen 2. I like the F90 here.
Chassis/Suspension- again hard to compare with two completely different cars. I love the mag ride in both my R8's it just soaked up the road. The communication of the compression and rebound with the car's body was excellent. The F90 shocks me in that its over 4300 lbs and just has amazing lateral grip with the proper flex that a driver should feel when pushing a car to the limits.
Interior to the M5- its far more luxurious and advanced of course
Tech to the M5- for obvious reasons- its not long in the tooth.

Again, a unique comparo and if I had to choose between my Gen 1 or the F90 its a no brainer. But if I had to choose between the Gen 2 and the F90.... I take both LOL. Its a tough one there. These are my thoughts.