He won his first major senior title in 1990 taking out the New South Wales Championship at his home track, the Newcastle Motordrome, which had become the centre of Solo racing in NSW following the closure of the Liverpool City Raceway in 1989 and with the Sydney Showground Speedway only holding one or two meetings per year.

He then won the Billy Sanders Australian Open on 28 December, defeating Leigh Adams, Sam Ermolenko and Troy Butler in the final.

A week earlier he had finished second to Australian teammate and local rider Shane Bowes in the "West End Speedway International" at the Wayville Showgrounds.

During his first ride of the meeting (Heat 3), and after leading three-quarters of the race, he was passed on the inside of the back straight by Jason Lyons.

Going into turn 3 Wiltshire fell while attempting to re-pass Lyons on the outside and slid into the safety fence, suffering terrible back injuries and multiple fractures of the Pelvis which forced him to spend a number of days recovering in the Royal Adelaide Hospital.

After making a comeback to racing in Germany during 1997, Wiltshire won his first Australian Solo Championship in 1999 at the Olympic Park Speedway.

Brady Kurtz from Cowra and Max Fricke from Victoria rounded out the podium places with Wiltshire himself on hand to award the winners trophy's.

Wiltshire moved up to the first division in 1990 with Reading Racers[10] where he was voted British speedway rider of the year after finishing third in the World Final at Bradford.

[13][14] Following his crash at the 1992 Australian Championships which had forced his retirement, Wiltshire made a comeback in 1997, riding in Germany in a bid to gain a place in the Speedway Grand Prix after being denied a licence to race in the United Kingdom.

Wiltshire first made his mark on the international scene when he was a surprise qualifier for the 1990 Individual Speedway World Championship to be held at the Odsal Stadium.