You're spoilt for choice if you wanted to go for a 2-2 exhaust system, but there isn't a massive selection of 2-1 exhausts for the Z, in fact only five that I can think of.

MTC - Low-priced (which you've already got!)
Exan - Mid-priced (three styles in three different materials)
OTR - Expensive to very expensive (with a variety of can choices including Akrapovic)
X-Racing - Mid-priced (good if you like cans in a vast array of colours)
Dominator - Cheap and cheerful (the budget option)

Horses for courses really - all depends what floats your boat and how deep your pockets are.

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