Cabin fever is in full effect.  I know it's not Maryland, but I'm taking my RX7 autocrossing at Hershey Park on March 29 & 30 with the SCCA.  It's only 90 minutes from Baltimore if anyone wants to hang out.

My FC is LT1/T56.  I am running kyb agx's with Suspension Techniques springs and sway bars on mine.  I drive it on the street and autocross it.  The front sits a tad lower than the rear, but you'll have that with an LT1 vs an LS1.   I really like them. 

Is this car an original Turbo II?  Does it have a Turbo II rear diff in it?

I would bet money you wont have any crackly ass sound as long as you have mufflers at the exit too

This is key.  Don"t lose the rear mufflers, just add the one up front.  A straight through muffler like a Magnaflow shouldn't cost you hardly any hp.

What kind of throttle body is on it? Stock or aftermarket?.  Has someone adjusted the closed throttle stop screw?  Possibly to the point that the IAC is being bypassed? I have had issues with an aftermarket 58mm t-body bypassing the LT1's idle air circuit inside the intake manifold and causing an erratic idle.  Also, make sure there are no vacuum leaks (even between the MAF and T-body).

I am actually using a caprice alternator from powermaster with my f-body harness.  I found a wiring diagram for the caprice.  You should be able to wire the brown wire going to the "L" terminal of the alternator as stated before. (this wire also runs through connector C205 pin"C")

That wire needs to come from an ignition switched 12 volt source, then run through a 470 ohm 1/2 watt resistor.

Then just disconnect the other brown wire going to the "F" terminal (or maybe "I" terminal).  This should rewire it like all F-bodys and work fine.

I used one of these mufflers on piglet's ls1 fd.  His motor is stock for now.  JTR headers, 2.5 dual in/out x-pipe magnaflow muffler just behind the trans, then y-pipe back to single 3.5, finished off with a 3inch 5x8x14 magnaflow muffler.  Car sounds as quiet as a stock camaro at warm idle, sounds great under normal driving but not excessive at all, and screams when you get on it.  For your hp level, I would personally try the 3 inch x-pipe muffler up front, then y back to a single 4 inch.  A 4x9 muffler tucks good up into the driveshaft tunnel.  I dont think the 5x11 will fit, but magnaflow makes that muffler in a 5x8 which would.  Just my .02.  Good luck.  Build looks great btw.