FREEWILL overcalls

This is a 2-suited overcall system, which can bid all hands with at least 4-4 in the suits opener didn't show. All you need is two 'decent 4-card suits' ('decent' = QTxx, Kxxx, xxxxx or better)

The advantages are clear: 2 suits are known, partner can preempt like hell, and you can intervene a lot more than the usual systems. The overcalls are natural, to put maximum pressure on opponents.
Ofcourse there are also some disadvantages. The structure needs a powerdouble, and sometimes, when it's not our hand, you tell opps a lot about your hand!

General principles:
1m-2m shows 44+M
1M-2M shows 3-suited with short M
1X-1NT shows 44+ in the lowest unbid suits
1M-2m shows 44+OM-m

1♣-?
Dbl = powerdouble, 15+HCP any
1♦ = 5+♥
1♥ = 5+♠
1♠ = 44+♠-♦
1NT = 44+♥-♦
2♣ = 44+♠-♥
2♦ = normal ♦ overcall, (5)6+ card suit
2M = weak, 6+M
2NT = weak, 55+♥-♦

1♦-?
Dbl = powerdouble, 15+HCP any
1M = 5+M
1NT = 44+♥-♣
2♣ = 44+ ♠-♣
2♦ = 44+♠-♥
2M = weak, 6+M
2NT = weak, 55+♥-♣
3♣ = constructive ♣ overcall, 6+ card suit

1♥-?
Dbl = powerdouble, 15+HCP any
1♠ = 5+♠
1NT = 44+♦-♣
2♣ = 44+ ♠-♣
2♦ = 44+♠-♦
2♥ = 3-suited with short ♥
2♠ = weak, 6+♠
2NT = weak, 55+♦-♣
3m = constructive m overcall, 6+ card suit

1♠-?
Dbl = powerdouble, 15+HCP any
1NT = 44+♦-♣
2♣ = 44+ ♥-♣
2♦ = 44+♥-♦
2♥ = normal ♥ overcall, (5)6+ card suit
2♠ = 3-suited with short ♠
2NT = weak, 55+♦-♣
3m = constructive m overcall, 6+ card suit

Over the powerdoubles we use Fantunes-style negatives followed by Gazzilli 2♣ relay to show 19+HCP (or 15-18HCP with ♣).