Which N20 kit??? What to expect???

I'm in the n2o market too. I'm researching it and think I'm down to 2 companies - NOS and NX. I think want to run 125 or 150. My next mods, before I get it are gonna be 1.6 rr's and up/lwr rear ctrl arms. Looking at my mods, is there anything else I should do first - clutch/tranny/shifter or full exhaust??? Or, should I wait on the exhaust and wait for the clutch/tranny to blow up?

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'90 LX 5.0; 12K original miles (no sh*&); 3.55 gears; pulleys;Edelbrock Performer Heads; BBK shorties; MSD 6AL box w/ blaster 2 coil; Motorsport E303 cam; Pro-M 75mm MAF; BBK 70mm TB; Eibach spring kit; Southside welded subs; K&N cone filter charger; Hurst shifter; fiberglass turbo hood; A/C-less; rear seat-less; cat-less; 2 chamber Flos; Corbeau racing seats (fronts);
30# injectors; JMS Chip; 190 lb fp; TFS track heat Intake (12.299 @ 113)