The Cars
Dad's 1999 S80 T6 has 105k miles, is driven like a grandmother every day, is Moondust with tan interior, has every option available in '99, needs some suspension attention (bushings probably), gets dino oil every 3k, new Michelins, and has an owner who is decidedly not a gearhead or DIY car type. My dad could grow delicious fruits and vegetables in the Sahara, and sell ice to an Eskimo, but he's clueless with cars.
My 1997 850 T5 has 111k miles, is sometimes driven like its driver is being chased by an angry biker gang, is black with a graphite interior, has every option available in '97, also needs some suspension attention (tie rods), gets synth oil every 5k, has older Goodyear tires, and has an owner who is decidedly a gearhead and DIY type. I have trouble keeping houseplants watered.
The Observations
The S80 seats aren't quite as bolstered as my '97 850 T5 seats. Or their surface is more slippery. Or both. Whatever the case, it's the first thing I noticed. [Yes, I've driven his car many times before, but I'm going at this as though my observations are new, which many are.]
It starts fine, but I can hear the unlubricated bits of the engine for 2-ish seconds before the oil gets pumped up and onto them. It makes me cringe. My 850 does this, but it's far less prominent, and for half the time. Perhaps the S80's oil pump is at its end, or the oil weight is too thin.
The S80 gas pedal is a little touchy -- like American cars. The tip-in is RIGHT NOW. I don't like it. It's a cheap way to sell cars -- people test drive cars and it "fakes" power by making customers think if that's the result of just an eighth of the pedal travel, this thing must have loads of power. My 850's pedal is more gradual, something that was a revelation to me in 1986 or so when I drove my friend's parents' 1980 Mercedes 300D.
The S80 is a long-distance runner: there is zero driveline noise and zero road noise at 70mph. The only thing you can hear is air noise.
The Highway is where the S80 shines, it's longer wheelbase and comfortable seats making quick work of miles. The car just speaks to you... Let's go to New Mexico, or Utah, or... anywhere interstate highways go. Conversely, the 850's 4th gear ratio just isn't tall enough, as if the engineers foresaw 55mph speed limit signs stretching off into the distance. [And 1st gear is too tall. Go figure.]
I had much time in a very similar interior as the S80's when I shared a 2004 V70 R with my ex. The S80 and V70 center stacks were nearly identical. And you know what? I like my 850's interior better, especially the driver's environment, despite the seven years designers and engineers had to improve the P2 Volvo's functionality. The only exception is the instrument gauges, where the V70 R takes the trophy hands down. But I'm comparing the S80 and 850, so back to those.
In the bright Colorado sun the S80's dash reflected badly on the inside of the windshield. Bad. I don't know how to solve this, except by getting an aftermarket dash mat, a dark one to absorb all the light. This is the primary reason I like dark interiors rather than Volvo's brighter tan ones.
I've always thought the P2 radios were rather fiddly and fussy, instead of doing what you want them to do and getting out of the way. My dad's S80's radio is no different. The source (CD/FM/AM) dial flies through the choices at even a small degree of input. I like my 850's 816 model radio's buttons.
The Moondust paint I like for practical reasons: doesn't show dirt, scratches or swirl marks nearly as much as black paint. And it looks worlds better at 14 years old than my 850's black paint did at that age.
Engines
The twin-turbo S80 powerplant is George Clooney to the high-pressure, single-turbo's Johnny Rotten. It's linear, strong and quiet. My 850's 222 horses come crashing in all at once when the tach hits 3500. Too bad the T6 found itself mated to weak transmissions the first half of its corporate life. This engineering decision disaster is infamous among us gearheads, and is unfortunate, to say the least.
Neither transmission feels very good or bad (excepting durability, where the 850 has the edge), so I'll leave it at that.
There you have it, my S80 vs 850 comparison. Just like the big car magazines do, only 14 years late.
