I just installed a downpipe, Bonez high-flow cat and the Apex N1 Dual cat-back.

I noticed some smoke coming out the exhaust when i rev it up and there is some black residue in the tips, when accelerating hard i can feel it choke and cut out and it sorta backfires.

Is my A/F ratio out of whack now that I have a crazy flowing exhaust? Should I get an aftermarket air intake soon?

I have had the car for about 7 months. Here is a list of mods/fixes:

Silver 1993 Base
New Engine
New Twin Turbos
New Transmission
Replaced O2 Sensor
Bonez 3" SS Downpipe
Bonez High-Flow Cat
Apex N1 Dual Cat-Back
Cusco Front/Rear Strut Bars
M2 Toe Links
M2 Trailing Arms