Where is the best place to buy a lightweight pulley for my 1.8 zetec black top not fussed and if its under drive or not

Crank pulley? If so don't bother wasting your money. Any gains are miniscule and it will be detrimental to the life of the crank.

I didn't ask for opinions on them I asked where tho get one lol I work for a lotus race team and we have proven they are worth having if you have a lightweight flywheel as well without the lightweight flywheel they aren't worth having sorry but they work

Which Lotus race team? My best mate worked for Lotus for many years after he graduated, he used to get the high mileage test vehicles for a weekend quite regularly since he came back to Plymouth quite often. Many happy memories of chasing superbikes in a V8 Esprit! (which apparently suffered from some torsional crank vibration issues...).

Lightened flywheels absolutely give good gains, but the moment of inertia of a crank damper is a small fraction of that of even a lightened flywheel so there really is very little to had. Unless you are running in an extremely competitive race class the disadvantages must greatly outweigh any tiny benefit.

If you are desperate to spend some money, then TurboSport sell a pulley.

[Edited on 28/1/13 by MikeRJ]

Standard zetec pulleys have a damper built in. This stops the neck of the crankshaft wobbling around and destroying the oil pump.

Stick with the standard one.