Yeh something there would be good as I have been on 100 rep for a long time now and gone through many phases of 'Double Rep' bonus stages etc which as you say is a bit of a shame, I still have no where near completed the Underground either,
I got to the Viper GTS so I could use it for the 'TUNER TRIALS' then decided to max out every single car I had from early stages to latest! I have either got them maxed out or just have 6 boxes with 'REBUILD' and a 'PADLOCK' icon next to it in each box like I did with the 'Snoop Dogg' car.
All these are missing BP's but are maxed out to the amount of stars I have for them
Dodge Charger R/T = 4 Stars and 5/20 BP's
Snoop Dogg Dodge Challenger SRT8 = 2 Stars and 0/6 BP's (NEVER SEEN ANY REMOTE CHANCE OF GETTING THESE) *EDIT* Until now in the 'Bonus Envelope'.
Skyline GT-R BNR34 = 5 Stars and 15/40 BP's
Ford Mustang Hoonicorn = 2 Stars and 5/15 BP's
Lamborghini Diablo SV = 6 Stars and 12/40 BP's
BMW M4 F82 (Razor) = 6 Stars and 5/25 BP's
Jaguar F-Type = 6 Stars and 8/25 BP's
Lamborghini Huracan (Greyed out as not unlocked but is there!) = 3 Stars and 4/35 BP's
Ferrari LaFerrari = 4 Stars and 21/35 BP's
but cannot rebuild until I have all the BP's but it's looking good mate!
Maybe they making it easier now cos there's a new game coming out or something??