If you want to give your own head a p&p, I say go for it. I did one on my dads car when we replaced the head gasket and valve seals and im in the process of doing my own. You might notice a bit of gain depending on your mods and its not that hard. The Standard Abrasives site is a good one to look at i found, just remember they are doing steel heads. In our case, aluminum is a bit harder to grind because of its tendancy to clog up the grindstone. Use grinders grease when your doing it and it should save you some trouble and possible injury. When hot aluminum gets into grindstone and heats up, the stone could shatter and thats bad especially when its spinning at a few thousand rpm.