More than 7,000 tickets have been sold for the Minnesota vs. Iowa Showdown, the season-opening wrestling meet between top-ranked Minnesota and No. 3 Iowa at the Xcel Energy Center on Friday, Nov. 15, at 7:30 p.m. Only 2,000-plus seats remain in the lower bowl of the 19,000-seat downtown St. Paul arena.     Tickets for the Showdown are available through Ticketmaster at the Xcel Energy Center Box Office, all Ticketmaster locations, at 651-989-5151 or online at www.ticketmaster.com. Ticket prices are $41.50 for lower level and floor (mat-side), $21.50 for lower level, $16.50 for club and upper level sides, and $11.50 for upper level ends. Groups of 10 or more can receive a $5 discount per ticket by calling 651-312-3486. All University of Minnesota students also receive a $5 discount with a valid student ID.    A follow-up to the extremely successful Border Brawl, held last season at Target Center in downtown Minneapolis, the Showdown features the two-time defending national champion Golden Gophers taking on arch-rival Iowa, a perennial contender for the NCAA crown. Like the Border Brawl, the Showdown will include an in-arena master of ceremonies, highlight videos, instant replays, taped and live interviews with wrestlers, coaches and fans, pyrotechnics, and much more.    Last season at the inaugural Border Brawl, top-ranked Minnesota defeated Iowa 22-15 in front of 15,646 fans. The meet set an NCAA attendance record for a collegiate wrestling dual meet. This year's Minnesota vs. Iowa Showdown will take place on the night before the Minnesota vs.Iowa football game at the Metrodome on Saturday, Nov. 16.