I don't agree that the Selespeed is any more trouble than the rest of the Stilo. At this age there are three likely problem scenarios: 1) worn out clutch, 2) pressure accumulator sphere lost its pressure, 3) pump brushes worn out (at high mileage). All these can be fixed.
The accumulator sphere seems to be appearing as a common fault just in the last year or two. Diagnostics software makes it easy to diagnose. The sphere is readily available as a genuine replacement part.
Old clutches get heavy and jerky, just as they do for manual-gearbox cars. You can expect about 120,000-150,000km from the clutch before it gets unduly jerky. Then, you need to budget for its replacement. That's pretty much right on 83k miles. The job is similar to what you need to do on a regular manual-gearbox car, except there is a bit more stuff to take off.
The pump motor can be dismantled and inspected as a preemptive strike, like you would for checking starter motor and alternator brushes.
I just want to point out that the mechanical part of the gearbox is strong and better engineered than the 1.2/1.4/1.6 gearboxes. Worn synchro or noisy bearings are unknown for this gearbox in the Stilo, and it would be fair to expect 200,000km+. It is the same gearbox basic design as used in the old Alfa 164 V6. Some of those are over 400,000km now.
Can't really say the same for the other gearboxes used in Stilos (look how many people have had the exploding 1.6 diff), so I don't agree about the Selespeed being thought of as 'troublesome'
The actuator (i.e. the Selespeed part) was a complete redesign compared to the actuator in the Alfa 156/147 Twinspark (4-cyl). Many people assume it's the same - it's not. The Stilo design is much better and has since been adapted for the smaller-engined FIATs (Dualogic) and the larger-engined Alfas (the fairly-rare 156/147 GTA V6).
I thought I had a Stilo Selespeed problem once - when I could only get 1st and 2nd gear - but it turned out to be a MAF (airflow sensor) engine problem!
I have quite a bit of experience with 156/147 Selespeed problems which were happening five years ago. Some electrical (connections, potentiometers, electro valves), some mechanical (snapped mountings in gearbox, synchro problems), leaking clutch actuators, collapsed release bearings. Now that Stilos are older than the Alfas were, I can safely say that in my experience they have avoided most (if not all) of these problems
I suppose advice here is going to be biased, but let's just say there are a load of other problems likely to afflict a Stilo other than the Selespeed. If you get a good Stilo, it will be a faithful friend, and if you get a bad Stilo, it will always be a lemon regardless of mileage.
-Alex