Quote Originally Posted by David88vert
Can you hold the throttle exactly at one rpm while driving down the road, plus look at your wideband O2 guage, plus adjust the laptop - all at the exact same time? Do you have datalogging? If you answer no to either question - rent a dyno. It's cheaper than a car wreck.....

Spend the money and do it right. Use street tuning only after you have it pretty much on the money.
don't forget tuning timing on the street is pointless since you can't see gains/losses...the butt dyno is very deceptive.