The answer to the former is Castres Olympique. Munster have played the French side 10 times in the competition and beaten them in seven of those games. In doing so they scored 25 tries and conceded 11.
Lee Jarvis of Cardiff is the man who can claim the record for scoring the most points against Munster with 27 for Cardiff in the 1997/98 season.
In total, Munster have played 90 games in the Heineken Cup. They have won 62 and lost 27 with only a single draw, coming against Neath back in the 1998/'99 season. Those 90 games have produced 235 tries, 155 conversions, 257 penalties and 14 drop goals for a grand total of 2,298 points.
The table below shows Munster's season by season record:
Munster will face Gloucester in their quarter-final this weekend. They have played against the English side on four previous occasions, with the honours even to date.
Both sides have won their home games against the other. They first paired off in the pool stages of the 2002/03 season with Gloucester winning the opening encounter by 35-16. The return leg has become known as the 'Miracle Match' as Munster notched up the four tries and points difference required to progress from the pool stages.
The table below shows the list of clubs Munster have played in the tournament:
Munster have reached the final on three occasions. They lost to Northampton in 2000 and to Leicester Tigers in 2002 before their historic win in 2006, but their involvement in the tournament goes right back to the 1995/96 season and their first game against Swansea, which they won 17-13.
1995-96: beat Swansea 17-13 (h), lost to Castres 12-19 (a)
1996-97: beat Milan 23-5 (h), lost to Cardiff 18-48 (a), beat Wasps 49-22 (h), lost to Toulouse 19-60 (a)
1997-98: lost to NEC Harlequins 40-48 (a), lost to Cardiff 23-43 (a), beat Bourgoin 17-15 (h), lost to Cardiff 32-37 (h), lost to Bourgoin 6-21 (a), beat NEC Harlequins 23-16 (h)
1998-99: beat Petrarca 20-13 (h), beat Neath 34-10 (h), lost to Perpignan 24-41 (a), drew with Neath 18-18 (a), beat Perpignan 13-5 (h), beat Petrarca 35-21 (a), Q-F lost to Colomiers 9-23 (a)
1999-00: beat Pontypridd 32-10 (h), beat Saracens 35-34 (a), beat Colomiers 31-15 (a), beat Colomiers 23-5 (h), beat Saracens 31-30 (h), lost to Pontypridd 36-38 (a), Q-F beat Stade Francais 27-10 (h), S-F beat Toulouse 31-25 (Stade Chaban Delmas), FINAL lost to Northampton 8-9 (Twickenham)
2000-01: beat Newport 26-18 (h), beat Castres 32-29 (a), beat Bath 31-9 (h), lost to Bath 5-18 (a), beat Newport 39-24 (a),
beat Castres 21-11 (h), Q-F beat Biarritz 38-29 (h), S-F lost to Stade Francais 15-16 (Stadium Nord)
2001-02: beat Castres Olympique 28-23 (h), beat NEC Harlequins 24-8 (a), beat Bridgend 16-12 (a), beat Bridgend 40-6 (h), beat NEC Harlequins 51-17 (h), lost to Castres Olympique 13-21 (a), Q-F beat Stade Francais 16-14 (a), S-F beat Castres Olympique 25-17 (Stade De la Mediterranee), FINAL lost to Leicester Tigers 9-15 (Millennium Stadium)
2002-03: lost to Gloucester 16-35 (a), beat Perpignan 30-21 (h), beat Viadana 64-0 (h), beat Viadana 55-22 (a), lost to Perpignan 8-23 (a), beat Gloucester 33-6 (h), Q-F beat Leicester Tigers 20-7 (a), S-F lost to Toulouse 12-13 (Stade Municipal, Toulouse)
2003-04: beat Bourgoin 18-17 (a), beat Benetton Treviso 51-0 (h), lost to Gloucester 11-22 (a), beat Gloucester 35-14 (h),
beat Benetton Treviso 31-20 (a), beat Bourgoin 26-3 (h), Q-F beat Stade Fran?ais 37-32 (h), S-F lost to London Wasps 32-37 (Lansdowne Road)
2004-05: beat NEC Harlequins 15-9 (h), beat Neath-Swansea Ospreys 20-18 (a), lost to Castres Olympique 12-19 (a), beat Castres Olympique 36-8 (h), beat Neath-Swansea Ospreys 20-10 (h), beat NEC Harlequins 18-10 (a), Q-F lost to Biarritz Olympique 10-19 (a)
2005-06: lost to Sale Sharks 13-27 (a), beat Castres Olympique 42-16 (h), beat Newport Gwent Dragons 24-8 (a), beat Newport Gwent Dragons 30-18 (h), beat Castres Olympique 46-9 (a), beat Sale Sharks 31-9 (h), Q-F beat Perpignan 19-10 (h), S-F beat Leinster 30-6 (Lansdowne Road), FINAL beat Biarritz Olympique Pays Basque 23-19 (Millennium Stadium)
2006-07: beat Leicester Tigers 21-19 (a), beat Bourgoin 41-23 (h), beat Cardiff Blues 22-12 (a), beat Cardiff Blues 32-18 (h), beat Bourgoin 30-27 (a), lost to Leicester Tigers 6-13 (h), Q-F lost to Llanelli Scarlets 15-24 (a)
2007-08: lost to London Wasps 23-24 (a), beat ASM Clermont Auvergne 36-13 (h), beat Llanelli Scarlets 29-16 (a), beat Llanelli Scarlets 22-13 (h), lost to ASM Clermont Auvergne 19-26 (a), beat London Wasps 19-3 (h)