We recently revised our Apple ( AAPL) price estimate upward to $337 (vs. market price of $259), based in part on the stunning iPad performance in recent months. To the consternation of e-reader and tablet players like Amazon ( AMZN), Sony ( SNE) and H-P ( HPQ), Apple registered strong sales of about 3 million units in the first quarter of 2010. We estimate that Apple's iPad business accounts for 8% of the $337 Trefis price estimate for Apple's stock, compared to around 6% for Macintosh Notebooks.We expect that Apple will sell more iPads in 2010 (10 million) than Mac Notebooks (8.5 million) and that iPad will continue to outsell Mac Notebooks over our forecast period. Furthermore, profit margins on the iPad (40%+) are expected to remain higher than margins on Mac Notebooks (about 30%). However, if demand for the iPad doesn't grow as much as we have forecast, this could result in 2% downside to our estimate for Apple's stock price.