Kościuch first rode for Unia Leszno – his hometown team – in 2000 but, due mainly to injuries, he played a peripheral role in the side until becoming more of a regular in 2005. During this time, he was runner-up in the 2002 Bronze Helmet (open to riders under 19 years-of-age), although his progress was halted by a freak crash shortly afterwards.
That occurred when he was forced on to the centre green in a meeting at Piła and suffered a split pelvis after hitting a tractor. And, he was to endure a further a setback in 2004, when a badly broken leg kept him on the sidelines.
He remained with the Leszno club, which races out of the Alfred Smoczyk Stadium, until the conclusion of the 2006 campaign prior to linking with PSŻ Poznań the following season. He made real strides in 2010 – with both Poznań and Örnarna in Sweden’s All-Svenskan League – and this caught the eye of British promoters with Peterborough winning the race ahead of Belle Vue to sign the Pole as a replacement for fellow countryman Kamil Brzozowski towards the end of June.
Having had his signing ratified by the Management Committee of the British Speedway Promoters’ Association and the Polish Federation, the Panthers’ management arranged for a van to travel across to the rider’s home in Leszno to collect two bikes and other equipment, thus ensuring he would be appropriately set-up for his debut in their colours.
He proved a popular signing at Peterborough and played a major part in clinching the Panthers’ Play-Off spot when he notched a career best 11+3 points in the club’s first-ever win at Swindon (from 26 attempts; 24 league, 1 KOC and 1 challenge) on 5 August.
Kościuch had to pull out of Poznań’s Polish Division One bottom four Play-Off encounter at Miskolc, Hungary, on 12 September due to an eye injury. Doctors informed him he would need several days to allow the injury to heal before racing again and that meant he also missed the first leg of Peterborough’s Play-Off semi-final tie at Coventry the following evening. He was fit for the second leg a week later, though, but his excellent tally of 9+2 points couldn’t prevent the Panthers from losing out on aggregate.
At the season’s end, the Pole had ridden in nineteen matches for the club and scored 83 points for an average of 5.04. He was again wanted by the Panthers in 2011, when they were late in getting underway following a winter-long dispute with the BSPA.
The Pole escaped virtually unscathed from a horror crash during a practice session in his homeland on 29 March. Although he was taken to hospital and kept in overnight, he luckily sustained only a deep gash to his forehead.
On 28 April, Peterborough produced a storming comeback to overcome table-topping Eastbourne in an Elite League encounter at the East of England Showground. Indeed, the Panthers recovered from 8 points down to eventually triumph 52-38; their win headlined by an impressive 11+1 points from Kościuch in a key reserve position, as he celebrated his 27th birthday in style.
The rider was taken to hospital on 7 July after suffering a suspected broken collarbone. He was brought down by rival Tomasz Jędrzejak in his second ride in the semi-final of the Polish Championship at Ostrów. ‘Norbi’ and the former Belle Vue racer were battling for third place in heat eight when they clashed. The following day brought better news that he hadn’t broken his collarbone, although he still faced time out on the sidelines due to a severe pain in his arm.
Late in August, it was revealed that Kościuch would be the man to make way for Michael Jepsen Jensen at Peterborough – despite registering a paid maximum tally of 13+2 points in a home match versus Wolverhampton just days before, on the 25th of the month. The Panthers said their decision was largely based around improving their away form, although they believed that the Pole did still have a future with the club.
The Leszno born rider wasn't initially in Panthers 2012 plans, but was re-introduced to the side in early June as part of a double-deal that also saw Krzysztof Buczkowski make a welcome homecoming. The Polish duo replaced the doubling-up pair of Rene Bach/ Lasse Bjerre and Jesper B. Monberg.
He made an immediate impact on his return averaging 7.17 (including bonus points) from sixteen Elite League matches and match-winning double-figure scores from the reserve berth quickly became the norm at the East of England Showground. There were also some improved performances on the road - with 9+4 at Poole during August being the biggest haul.
Kosciuch started the new season in March on a 5.50 average but after a poor run of results was dropped in early May for Danish star Nicolai Klindt.
However, in an ironic twist the Pole returned to the Showground as Kilndt's replacement on July 8 after the former Wolverhampton man struggled for points.