I am taking it to a good shop but since it's my first IRS car, i'm unsure if there is anything they should be aware of other than the usual?

I'm installing four new tires (Bridgestone RE960s) as the car's tires are worn but I'm also feeling a slight vibration through all speeds evident in the steering wheel (and the car body). I am hoping that both new tires and an alignment solve this, as I've replaced the ball joints, struts and rear LCA bushings this past summer.

All 4 wheels are adjustable (to some degree) so make sure you get a "4 wheel" alignment, not just a thrust alignment.

DEWFPO
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1998 S90 083,228 and 1995 964 154,100

ok, i do know that, just curious if there was any "best" setting as determined by Bricksters through the years.

to my eye, the rear suspension seems a bit complex, especially when I was thinking about replacing some of those bushings. no thanks.
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1991 745 & 1993 965 /// RIP: 86 764T; 79 262C

A competent shop should be able to handle the Volvo IRS just fine... As suspensions go it is not that complicated at all-it may be different than the "regular" Volvos but it's no big deal... Your vibration, however, may be due to a driveline issue and not suspension related.