Fabio-
A good stock Opel GT will accelerate at the same rate as a Ford Taurus. Period road tests indicated a quarter-mile time of 17.7 seconds - don't recall the trap speed off the top of my head. 0-60 times are in the 11 second range for manual, 13+ seconds for an automatic. If you're used to driving a Chevy Cavalier, a GT will feel pretty sparky; if you drive a Lexus as your primary car (nod to kristi here) the GT will feel kinda slow.
The real appeal of a GT (besides *the look*) is the handling. A stocker GT will hang with the best of the pocket rockets inna turn. The car has what is called a front mid engine configuration, as the engine is behind the front wheel centerline and protrudes into the interior compartment. Add in a solidly located rear wheel drive axle, and the road 'feel' is second to none, in my opinion.
Just drove Maggie the Opel to work today; decided to try out Emily's tune-up (my 11-year-old daughter) on the freeway...
Amazing.
Keep in mind Opels were designed to stay planted and running on German Autobahns - the result is a 30 year old car that feels as good as a modern car at speed. Maggie the Opel was completely nonplussed at 85 MPH - got all sorts of neato looks as she whizzed by traffic going 10-15 MPH slower. If I were to upgrade her wheels and tires, there are few performance vehicles that could hang with her in turns.
Proof of this is found in SCCA IT class racing. 30 years after their debut, Opels are STILL competitive at weekend track events. There are a pair that race here at Waterford Hills, (a GT and a Manta) and they consistently turn some of the lowest lap times - often within a second of the 'Vettes!
The downside of owning an Opel is that they are a 30-year-old car. They WILL require frequent maintenance and tinkering to keep them 'just so'. If you don't like spending a day or two a month working on your car, or if car-related problems tax your patience - an Opel is not for you. If you want to stand out from the crowd and are willing to invest the mechanical effort to do so, then there are few cars that will provide as much bang for the buck!