Before you spend that kind of money, consider that a local racer just won the World Masters TT Championships (30-39 age group) without a PM. He told me he'd like to have one someday, but they are just too expensive and the team won't pay for them. He said some of the lawyers on his team have PMs.
He has a degree in exercise physiology, is a personal trainer, and does use an HRM. He said he tapes over the display while racing so he's not distracted or limited during the event, but still has the info for downloading later.
Another older guy here won his age bracket in the National Senior Olympics last fall. He doesn't even use an HRM in training.
Of course, anecdotes prove nothing. It's just that the fastest guys I know seem to be relatively unconcerned about a lot of the technical stuff. They look "normal", not super muscled or anything, and their training programs seem remarkably mundane or even unstructured compared to the programs I've read in books.
It's almost like they have some hidden talent that I'll never possess