What you want then is a series one 106 xsi/rallye with a 16v engine in then. Seen plenty of xsi's especially go for 1200-1500 for a nice one. They are about 100 kilo lighter too. Simple breathing mods manifold, decat etc will give a good solid 130+ bhp and in an 850kg car, it won't be shy. Just be sure that it has retained the xsi/rallye box for even quicker acceleration or at least the gti/vts box. Avoid anything with vtr/1.1 boxes as they are horribly long ratios.
Join 106rallyeforum.com and have a look at the classifieds.
http://www.106rallyeforum.com/forum2008/showthread.php?t=64995 this one looks ok and you could prob get it for 1500 without the spares