Its time to get the hands dirty.
From the sounds of things, this shops shortcommings is going to force you to learn rather quickly how to do your own work. Heres a few things I would check out right away, before you drive it again.
First, if you suspect the transmission is leaking then try to clean off the tranny as well as you can with degreaser wipe it dry and let it sit for a day or two, and check it again. This way you'll have some indicator of where the leak is comming from, or if it is leaking. If you have a gear hesitating it could easily be because of the fluid you might have lost. Try filling it back up with Pennzoil Syncromesh once you target and fix the leak.
If the stalling problem is electrical it could be several things. First thing i would do is check the Ignitor, which should be from the 3SGTE motor. If you can start up the car then most likely the battery is OK, but if it hesitates alot then give it a check on the voltimeter.....just because its an Optima doesn't mean it couldnt somehow go weak or dead over the period of the swap.
Check that the harness plugs are fully connected and that the fuses are all in tight and not blown. Several recent swappers have had issues related to something simple in their electrical, like zipstrips and x itchyb x, so starting there would be wise as well.
Your exhaust soot on the tip shouldnt be a huge problem, since the motor probably hasnt been run in a long time and is just burning off some excess buildup and gunk. If you have alot of smoke on startup or see heavy white/blue or black smoke after the car is up to temp, then you might have a problem.
As far as your boost gauge working, look under the FI forum stickies and you'll see this post on 3SGTE maintainence and vacuum info.
http://www.6gc.net/forums/index.php?showtopic=23139Hope this helps a little. Good luck.
EDIT- this also reminds me, you should be religious about the condition of your oil with a new swap.....change it out after your first few hundred miles, and then again after only another 700-1000 miles. Make sure its clean and isnt burning off or dropping in level excessively.
This post has been edited by Silver94CelicaOwner: Mar 6, 2006 - 3:06 PM