A dime-a-dozen JDM D15B will run you around $400 and it will bolt right up to your existing mounts and current B7 transmission. Home-brewed T25 turbo kit w/intercooler will tack on another $900. It will put you around 170 whp, which is more than a "feasible" B-series swap any day. Whereas if you wanted a good, reliable, complete swap, it can be had on ebay for a whopping $2600 (not counting mounts and shift linkages by the way)
http://cgi.ebay.com/JDM-B16A-3rd-Gen...QQcmdZViewItem