Re: A2 or Scirocco? (QcGTI)
From your description, the Scirocco you're looking at isn't exactly stock - in that case, if you're ultimately looking to modify your car, it's probably your best option since it's already been done. My "stable" includes both an '88 16v Scirocco that's prepared for the Grassroots Motorsports challenge and a '87 16v GTi that's prepared to SCCA's IT specs. Therefore, my opinions are biased towards performance and not an emotional attachment to exterior design. SO if you're a Scirocco fan b/c it looks cool, read no further.
However, bear in mind that the Sciroccos (or any A1 chassis) isn't the best design effort that VW ever put forth. In fact, the only saving grace to the 16v Scirocco is the lower suspension tie-bar which is still a far cry from the sub-frames that were standard on A2s. The A1s are markedly lighter than the A2s (except for the 16v Scirocco which weighs in roughly the same as an early A2 GTi 16v) which means that the car feels more like a go-kart. While the weight advantage of the A1 makes the car more nimble, suspension design and chassis flex without a cage make the car less stable in heavy cornering. The last issue with any A1 chassis car is the motor mount design - from what I can discern from these digests, the A1 chassis isn't capable of handling more than about 175 hp without significant chassis reinforcement. Even in stock trim, the motor mounts are a "normal wear item" just like the mounts in the 944 (VW's bigger and more expensive brother). On the plus side for stock 16v Sciroccos are the 10.1" brakes which make a relatively heavy car stop quite well. Furthermore, due to the lower roofline, the centre of gravity is lower which aids in cornering.
The A2 cars are heavier by 200-300 lbs. With that extra weight comes some added track, a front sub-frame and a more logical and durable engine mount system. While the A2 isn't as nimble, the added track and superior suspension design give the car more stability, even with the higher center of gravity (which can be offset by lowering the driver in the chassis). The biggest negative to an A2 are the miserable 9.4" brakes - the SAME brakes that were fitted on the A1 GTis!!
Both cars have their specific strengths and weaknesses. In my case, I'd been searching for an A2 GTi 16v to use as a commuter car but happened upon the '88 16v Scirocco instead. While not being a fan of that genre Scirocco (I prefer the Mk1 but that's another story), I must say that the car has impressed me with it's appearance and fairly sedate ride. The '87 16v GTi is also a decent car although I can't say that I'd be as impressed with a base-model without the accoutrements that are included with the GTi/GLi - interior, 4-wheel disc brakes and so forth. Suffice it to say that the Scirocco is nice looking and a relatively comfortable commuter car, the GTi is a decent basis for an IT car with good availability of go fast bits.
In this case, if the Scirocco described is the one you'll purchase - buy it instead. It sounds like it already is chock full of parts that are (hopefully) already sorted.