The biggest transfer of all time for Arsenal?

With this week being the 18th anniversary of Dennis Bergkamp joining the Premier League with Arsenal and Higuain’s transfer to the same team becoming closer to being finalised this week too, is this Arsenal’s biggest transfer in nearly two decades? 
In my eyes, Bergkamp is one of the greatest players to ever grace our league when he joined from Inter for a transfer of around £7.5 million under Bruce Rioch, but didn’t really hit the heights that everyone knows him for until a year later when Arsene Wenger was appointed. Now when Bergkamp joined he was a fully capped, respected international footballer who was expected to go onto great things and wasn’t deemed “a punt” due to every manager at the time recognising his ability, now I can’t think of any player that Arsenal that have signed since that could be in the same class as Bergkamp WHEN they were signed?
Arsenal under Wenger have been more insightful with players and signed more potential than established players. Before you start yelling Thierry Henry, Cesc Fabregas or even Robin van Persie at me, they were signed incredibly young and were moulded into the world class whilst at Arsenal, where as Bergkamp joined after playing 230 odd games and scoring over 110 goals for both Internazionale and Ajax. Granted, he was slightly moulded by Wenger and was placed under a stricter health and fitness regime and was used as a fulcrum by the Arsenal manager and is regarded as one of Arsenal’s best players.
On the flip side, Arsenal are appearing to be edging towards wrapping up a deal for Argentinian striker Gonzalo Higuian from Real Madrid  who has played 32 games for his national team and got 20 goals and over a hundred for Real Madrid since 2007 and largely he’s been playing second fiddle to other strikers. Now if/when he joins Arsenal, he will be not only young, but he’s really, really good and proved it in one of the best leagues in Europe.
I can’t think of anyone that has joined Arsenal with a higher than one in two goal ratio for his national team and near enough the same for his club team that is largely regarded as the second best team in the world. Arsenal will be buying a player who is a perfect fit for them and they haven’t had a goal poacher as of late who can latch onto the low crosses the wingers tend to play, and for only a reported £22 million, it could be a huge coup for the red half of north London and has potential to be buy of the off-season if Higuain replicates some of his goal scoring form for Madrid. I look very much forward to seeing him, lets hope he joins!