The stuff you are thinking of is called oil flush, im sure most motor part shops sell it. However there is allot of talk on the net about how flushing an engine can damage it....im not really 100% certain as ive only breezed through it myself, but id read up on it before you do it.
Cheap mods that id recommend:
Viscous fan delete.
very easy to do. All you need is an electric fan switch and an electric fan and shroud from the junkyard.
Fog your airbox.
Take out all the foam and plastic frame from inside your airbox.
Block the standard hole, and get rid of all the pipe work leading to it.
Cut a big hole in the front (below the level of the airfilter for obvous reasons)
connect a piece of flexi pipe to the hole and place the other end somewhere that it will get loads of air.
Fit an oil catch can.
described here
http://www.m42club.com/forums/showthread.php?t=5279in addition to that you could drill a third input in the catch can and connect it to your crank case breather

Hope that helps
Paul