Not sure about a vent kit on a 2.5 the plastic vent line the kits are supplied with would melt if it came in contact with the tuner.
Prime Marine 909-484-8338 is in your neighborhood and Mike can get you back on the water fast and probably has the seal kit.
If you want to handle it...
When I skied behind mine you could see water shooting up between the hull and plates through the hinges. But with 1000 plus hp never notices it from the drivers seat:D
If you launch in the salt water call Wayne:
West Coast Trailers  
Boat trailer dealer in Huntington Beach, California
Address: 15701 Container Ln, Huntington Beach, CA 92649
Hours: Open today ? 8AM?5PM
Phone: (714) 842-8040
They build a nice aluminum trailer :thumbsup
You can usually find used Snap-on boxes and tools for 25 cents on the dollar on E-Bay or Craigslist the HF or Craftsman boxes are not even close in quality IMO.
Skin cancer is the real deal had two areas cut out last year and the fucked thing was because I had Blue Shield Platinum Plan the doctor told me if I had cheaper Insurance they would have cut out both areas on the same visit. But with premium insurance they schedule two visit so they can bill...
Sears gel battery going on 4 years still holding a charge and they loose very little over the winter.
Another great option is to buy battery's from Summit Racing 100% warranty great pricing and free next day delivery.
If your battery is still in the warranty period just call them up...
Mercury stopped making 300x long blocks and the few that where left in inventory sold very quickly. Most likely your dealers is getting a re-manufactured long block check the Mercury part # 61-840756A04