That helped edge pre-tax profits upwards from £716,699 to £753,202 for 2013, according to annual accounts filed at Companies House.
The company, which operates dealerships in Dundee and St Andrews, said new vehicle sales were up by around 13 per cent which was broadly in line with patterns across the UK.
Used car volumes were up by eight per cent while margins on both types of vehicles improved by 0.4 per cent in the year.
The servicing arm was down slightly which Barnetts said was mainly because of the large number of service plans being offered by car manufacturers as a way to tempt customers.
However the general improvements in reliability of cars is also resulting in fewer breakdowns and less need for servicing outside of annual checks.
Writing in the accounts, the directors said: "We continue to monitor this position closely and are actively working to grow our after-sales business through creative marketing and customer-friendly initiatives."
The company increased its net funds in the year from £1.12m to more than £1.6m.
Average employee numbers were steady at 130 with staff costs growing from £3.3m to £3.4m.
Directors' remuneration increased from £242,000 to more than £295,000 with the highest paid seeing their rewards go from £122,928 to £178,655.