The Alfa Romeo GTV had been around for quite some time when they decided to put the 6 cylinder from the Alfa Sei into it. And this totally changed the car and its positioning.
The Alfa Romeo GTV 6 was directly competing with the contemporary smaller Porsches and for example the Renault-Alpine A310. The price point was set at around half the value of a Ferrari 308 GTB, so it was somewhat affordable.
The Alfa Romeo GTV 6 is a car where the engine is (almost) everything. And what an engine this was! In the GTV 6 disguise it developed roughly 160 HP, featured a fuel injection and produced an unbelievable soundtrack. Different to other cars where you need to wind down the windows this soundtrack is always extremely present also in the interior and reason enough, not to order a stereo for this car. Why should you? The rest of the car was okay but not really great. The transmission mounted in transaxle setting was difficult and not exact to operate. Breaks and suspensions were acceptable but not really performance car like. The interior was improved against the older GTVs but still much less attractive than for example what came from the UK at this time or even partially from Germany.
But as a package it was a great car and the reviews from the different car magazines were quite positive, again especially for the engine. Fuel consumption was quite low too, performance with roughly 8 seconds from 0-100 km/h and 220 km/h top speed pretty competitive during the early 80ies. There was a kind of Mark 1 and a Mark 2 (with more plastic and some improvements). It was built between 1981 and 1986. Rust and corrosion were still a topic but less so than for the years before. The car sold quite well.
I haven't yet owned a GTV6, but it's one of the 80ies Alfas to consider and I believe there hasn't been one since then (maybe with the exception of the outrageously expensive 8C) that sounded as well as the GTV6.