OK things aren't as rosy as it initially looks. While the Kit requirements and costs have gone down, they races where you could win the kits have been removed and now you can only win 2 of a certain type per day through the new Tuner Trials (unless you pay real cash for more) this could mean a LOT more planning to make sure you are aiming for the right grade part on the right day, plus 2 a day means if you are going for Blue or Purple Kits you'll need at least 2 weeks to get them!
For me this means I can't both go for Green kits for my M4 and Blue for my Mustang at the same time and with only 2 weeks to get them I'm out of time, luckily (for me) I've built up quite a lot of Blue Kits because I couldn't afford to fit them but not for every type but I have next to none green.
A secondary but minor compared to the above issue is a large increase of the part needed to fit with the Kit to perform the upgrade, 4 for green, 8 for blue and 10 for purple. Annoying but manageable.
edit - some additional things I've discovered:
ALL Car Series races that were till 10 mins ago listed at replay-able have been removed. This means getting the daily reward "Win 3 Races in Car Series" will be a lot harder if you've reached the PR levels of all the races.
Underground Chapter 3 race 3: If you've won all the blueprints for the Fiesta the car is removed from the prizelist with money placed there instead, however the old trick of winning this race after getting all the blueprints still works as you are guaranteed to win a Full Street Class part, worth $3000(green)-5000(blue) if you sell it. Worth doing as it only costs 1 unit of fuel. This happens on any blueprint race that you have all the blueprints for that car.