i've got a lot of knowledge in this arena. rode powertaps for many years, built thousands of wheels, many of which had powertaps in them (yes, calibration very important), tested a few different powermeters out for slowtwitch.com and raced at a fairly high level.
425w for 30' at 82kgs is doable, of course, even for someone relatively new to the sport. BUT every fiber in my body tells me this is not an accurate reading if you did that at 60rpm. it's just so so unlikely. not impossible, but probably like 5th standard deviation sort of rarity.
let's just say it's totally legit, though. you'll still never ride pro cause you're too old. it takes too long to learn how to read a race and on top of that there are age limits (or at least there was when i was in it) at the entry level for professional teams (which virtually all US-based teams are). at least when i was racing here in the US the team's avg age was to be under 28 and half of the riders had to be under 28.
another thing that should be noted here: someone with big power numbers, like myself back when i was fit, can get on a fairly inexpensive bike while riding in running shorts and running shoes, and absolutely destroy all the local freds decked out in their assos kits on their $5K+ bikes with race wheels. so no, it does not need to be a super expensive ordeal right from the start.