Just the header with stock exhaust is going to give you an interesting experience. You'll have way more lowend on tap but the highway cruising isn't really going to improve. Before I had my cat-back done, just the header with otherwise stock piping kept throwing a CEL. Additionally, the resonator will no longer properly deaden the rasp. Above about 3,000-4,000 RPMs, you'll be making noises that will set off car alarms. =) If you want my old 2.25" o2-sensor-back system with a Magnaflow Wide Open Performance muffler on the end, drop me a line.
With the brace and the Pro-Kit springs, yes, the car will feel a lot different and better able to hold the road. Sounds like a good plan...good luck.
With the brace and the Pro-Kit springs, yes, the car will feel a lot different and better able to hold the road. Sounds like a good plan...good luck.