Sorry, I wasn't aware it had to be a fair comparison - just offering up a cheaper, yet just as effective base proposition - the 4WD elements is quite similar.
Yes the Syncros are only 90PS to start, but at £500-1000 to buy that leaves a lot of budget to modify them over and above a Rallye, where you've blown a minimum of £2-3k before you get going. Plus there are rather fewer obsolete and 'special' parts on the Syncro vs the Rallye - good luck getting hold of a new screen if yours gets a crack or chip in it (obsolete and no VAG stock left).
The Rallye had a serious disadvantage when it was on sale in the UK in that it was poisonously expensive and LHD. The Syncros were just 'rather expensive', coming with the added benefit of being RHD (I'm just finding out what a 'benefit' that is with mine now). The RHD high-tunnel shell means the cars are very UK-market specific, whereas the 63 UK Rallyes would be that much different to the EU version..... would they?