Exciting News! We are now open for business full time - see below for more info.
Originally the oil recommendation was straight 30 weight oil in the summer months and 10w30 in the winter months. That was with 80's oil technology. Oil technology has come a long way since then.
I like to use Rotella T diesel oil in my turbo car. 10w40 is what I use in the summer months.
Depending on the type of fuel you have available, it may be wise to add an octane booster. I have 93 octane premium fuel available at the pumps in my area. and have no issues of detonation. Some areas only offer 91 octane. If you decide you need octane booster additive, I have had really good results using Lucas brand octane booster in the red bottle. If you are still experiencing detonation, you need to look into other areas of the tune or the engine.
I like to use NGK UR5 (2771) spark plugs. They are one heat range cooler than stock. Gap should be set .035"-.040".
Stock boost levels should be 7-9 psi as long as you do not have any detonation. You can run higher boost with water/alcohol injection. The highest boost I have run with a stock turbo is 14 psi with water/alcohol injection.