There's been a lot of confusion on HKS exhausts and what the differences are in each one. Looking at the HKS USA website, it's not real clear on what the differences are. We're working on clarifying on the website, but I wanted to give an overview of the different options and exactly what the differences really are.
To begin with, there are two main categories of exhausts HKS has for the BRZ/FR-S. The Hi-Power and Legamax. Hi-Power is going to be the one that makes the most power, while Legamax is designed to be a more tolerable sound for daily driving but doesn't quite put out the same power.
Let's start with Legamax.
There are two types of Legamax exhausts. Legamax Sports and Legamax Premium. Legamax Sports uses a dual muffler design whereas the Legamax Premium uses a single horizontally mounted muffler. The Legamax Premium is available as a cat-back or axle-back, and the Legamax Sports is available with either single or dual tips.
Legamax Sports Cat-Back (Dual Tip)
Part #: 32018-AF009
MSRP: $1700
Stainless Steel Dual Tips, Dual Exit Exhaust
Legamax Sports Cat-Back (Single Tip)
Part #: 32018-AT041
MSRP: $1500
Stainless Steel Single Tips, Dual Exit Exhaust
Legamax Premium Axle-Back
Part #: 32018-AT039
MSRP: $899
Stainless Steel Single Tips, Dual Exit Exhaust
Legamax Premium Cat-Back
Part #: 32018-AT040
MSRP: $899
Stainless Steel Single Tips, Dual Exit Exhaust
Moving on to the Hi-Power exhaust, there are 3 options from HKS. The Hi-Power Spec L is available with either titanium tips or carbon-wrapped tips, and the Hi-Power Racing exhaust is a single exit exhaust that will give you the most power.
Hi-Power Spec L w/ Carbon-Wrapped Tips
Part #: 32016-AT023
MSRP: $980
Carbon-Wrapped Single Tips, Dual Exit Exhaust
Hi-Power Spec L w/ Titanium Tips
Part # : 32016-BT001
MSRP: $980
Titanium Single Tips, Dual Exit Exhaust
Hi-Power Racing
Part #: 32016-BT002
MSRP: $600
Titanium Single Tip, Single Exit Exhaust
In addition to the cat-back and axle-back exhaust systems HKS offers, we also offer 2 different header options and front pipe.
4-2-1 Exhaust Manifold (w/out cat)
Part #: 33002-BT001
MSRP: $799
4-1 UEL Exhaust Manifold (w/ cat)
Part #: 33005-AF018
MSRP: $1280
Front Pipe (w/out cat)
Part #: 33004-BT002
MSRP: $350
And finally, there are some combo packages available.
Exhaust Manifold & Front Pipe (*with* hi-flow cat) [fits 6MT only]
Part #: 33005-AT006
MSRP: $2200
Hi-Power Spec L w/ Carbon tips & Exhaust Manifold & Front Pipe (w/ hi-flow cat) [fits 6MT only]
Part #: 32025-AT001
MSRP: $3300
+
Legamax Sports Cat-Back & Exhaust Manifold & Front Pipe (w/ hi-flow cat) [fits 6MT only]
Part #: 32025-AT002
MSRP: $3160
+
Hopefully that clears up some confusion and helps you pick the right one!