More units of the 197bhp rear-wheel-drive car have now been received and a larger annual allocation secured for next year.
A company spokesperson told Autocar that roughly half of the 50-strong Subaru UK dealer network now have a BRZ on display, while the average waiting time to complete new orders has shrunk to between two and six weeks.
The company describes the BRZ as a sales success having sold out of its full UK allocation. It sold 100 units in 2012, and 120 so far in 2013.
By comparison, Toyota sold 1435 GT86 units in 2012 and 1060 so far this year. A Subaru spokesman said that Toyota's share of production was "several times" larger than Subaru's and European allocation of the BRZ was tight.
The spokesman said: "The BRZ will always remain a niche choice. Some people will like that".
Subaru has also confirmed that a new range of approved upgrade parts will soon be available to customers. The upgrades, sold by tuning company Pro-R, will cover suspension kits, exhaust upgrades and wheel and body styling options.