Continued: ls problems

someone was asking what all i had.....its just a 5G si with a LS swap...and a short ram intake....no exhaust....no VTEC....on my launches i had to start off rolling and then get on it (but they still would spin some), and then shifting into second i couldnt let off the clutch too quick or else they would start spinning again....also i recently added a DC SPORTS shortshifter.....basically im looking for some reasurance, i was kinda disappointed when all i could do was a 16 flat....hopefully with new tires ,a camber kit , and a shortshifter i can get down into the mid 15's......thanx for all of your help