Welcome to the forum Tim.
I'm in Windlesham so fairly local to you and I'm also a serial BMW owner. I took a workplace pension early when I was 55 and spent part of the cash lump sum on my first Coupe - 12 years on and I'm on my third!
The 3.0Si came as a 6 speed manual or a 6 speed auto, split about two thirds : one third respectively and as an SE or a Sport. The latter had the very desirable M-Sport seats as standard, albeit with stiffer, lower suspension.
Standard equipment was a bit mean although they all had electric seat adjustment with drivers' memory. Bi-Xenon headlights, heated seats, cruise control, Multi-Function Steering Wheel, cup-holders, rear parking sensors, Sat Nav, better stereo with more speakers were all on the options list so it's worth deciding which of those are "must haves" or "nice to have". Cup-holders and cruise control are the simplest to retro-fit.
You need to check all the things you'd check on any used car, but specifically look out for oil leaks from the cam-cover and oil filter housing gaskets which get brittle with age. Rear brake pipes are prone to corroding just in front of the passenger side rear wheel (I've had them replaced on two of my Coupes) and check around the edges of the tailgate for corrosion.
The engines are pretty bulletproof so don't be put off by 6 figure mileages - there are two people on here who have 200K mile Coupes!
Keep an eye on the Meets/Events section of the forum for possible get togethers, and enjoy finding the right one.
ETA Maybe this might be of interest?
We've been meeting up at this for years now, but several things put me off for a while - A3/M25 junction improvements, Black Swan refurbishment, Old Lane and Ockham Bites closure spring to mind!
Anyway I went last month and all was back to normal so subject to weather I plan to go to this one. And it really is weather dependent as parking is in the car park and overflow field.
For anyone who hasn't been before there is usually a really eclectic mix of cars, and some bikes, ranging from 30s Bentleys to road-going Ultima race cars with things like air-cooled VWs, Fast Fords, some...