Shares are up slightly in pre-market trading as the improving economy, and especially auto sales, enabled the satellite radio company to project that it will gain 1.5M subscribers in 2012 — up from its previous estimate of 1.3M. The forecast was part of Sirius XM’s Q1 report that showed net income of $107.8M, up nearly 38% vs the same period last year, on revenues of $804.7M, up 11%.