I have a 93 Touring, with 75K miles. Engine mods are as follows:

Rotary Performance SS Downpipe & hi-flow cat
Apex Super Intake
Efini Y pipe upgrade
Greddy Elbow and polished pipe kit
Boost guage

My question is, do I need to upgrade my engine management system (Apex or Haltech) before I can add a cat-back muffler? I am planning on going with the Racing Beat dual tip, as I like the stealth look of it. My fear is too many mods before upgraded EMS = toasted motor. The car is not a daily driver, maybe 200 miles a month, on nice days only. Any advice is greatly appreciated. Thanks!

 

Short answer...yes. It would be wise to upgrade your EMS in some way. You can go full standalone (Haltech, PFC, AEM) or at the minimum piggyback (S-AFC, AVC-R). The general rule of thumb is three mods, then go for the ECU. Are you seeing any boost creep/spikes right now? Also, you might look into getting an A/F gauge or an EGT gauge to watch for those lean conditions.

But I would suggest staying on the safe side...I put just a downpipe and catback on my car and easily saw 15 psi...turbos went buh bye after only 500 miles.

 

I have a 93 VR Base Model with the following mods:

Pettit Cold Air Intake
Pettit 3" SS Downpipe
Apexi Dunk Catback Exhaust
Power Pulley
8.5# Aluminum Flywheel
Engine Rebuilt @ 114k
Currently @ 118k

With these mods, I'm running 11-9-11 Boost.

I won't add Hi-Flow Cat until I can upgrade the ECU and add a boost controller, probably the Greddy Profec-B.

Otherwise, I'm cruising fine.

 

Yes please get an ECU. If you plan to keep the stock twins and just add bolts on then you can check the for sale section. There are a few ecu for sale for a good price.