Even though I don't already have this achievement, I can give you the tips I'm using to reach the 1660 power required to beat Frank Milius.
First of all :
There are only 3 vehicles that can reach 1660 Power :
- Lamborghini Veneno (which I would recommend to choose)
- Hennessey Venom GT (only buyable with gold, and you'll never get it with in game gold because the total gold I earned by now is around 100, because I've won an event giving me 50, and that car is buyable for 1250 Gold...so, if you pay to win, choose this car, but in this case, you won't need any help as you'll be able to buy money to upgrade faster)
- Lykan Hypersport (costs less than the Veneno, but you'll need to spend lot more money to upgrade it to reach the required power so don't choose it)
Then, if you follow what I say, considering that you choosed the Veneno, to best upgrades config I would tell you (well, at least that's what I'm trying to get and it looks the cheapest way) is :
- Engine => Level 4
- Gear => Basic Level (costs too much for only +3)
- Nitrous => Level 2 (upgrade/cost is lower than Engine, that's why it's only 2)
But you can also choose to upgrade Nitrous to level 4 and Engine to level 3, but I personnally don't think it's cheaper.
Last but not least, to get your upgrades, you'll need cash.
But how to farm it ?
Two methods. I used the first one until I was able to get enough gold to race, beat and earn the Lamborghini Countach.
First method : To begin, do you best on Stunt races and Destruction races, they give you a net of 15'000 minimum each time you do them. Plus the Stars bonus when you get them the first time.
Always do your Daily test, 15'000 bonus and even more with in race bonuses, but over anything else, you can't lose this race (well, at least I never lost one, and can't see how to lose there)
Finally, you'll farm Cop chases (anyway you need to complete them all to get this other achievement)
I used to only reach the 11th mission on 12 with my current power of 1611. The power required to complete the last one is 1640 (it's gonna be on your way to end this game). Farm it. I got around 20'000 $ everytime I completed it, but be careful, it's a pain in the ass to win this. I mean, you'll win it, but the Police Countachs are really boring...Never crash, always boost when you can, and create chaos to earn even more nitrous to make your way to the end.
With that method, you'll basically get to the end of the game, but it's kind of boring, and annoying when cops get you in those missions.
Second method. I recently got enough gold to earn the Lamborghini Countach by beating the 4th boss. My strategy was to get it, complete the Restricted run with it (1st Run is with the Countach), and then get to the second Restricted run playable using the Veneno.
This method is easier than the first, but requires you the Countach, that's why I recommend to 1st method if you don't have many gold.
Completing the run with the Veneno nets you 17'500 each time. Plus bonuses which gets me around 20'000 to 25'000 each run. And the fact this method is better is because the runs are shorter than a Cop chase, and less stressing as the goal for that run is to get 11 jumps. Really easy. My best was around 15, and my best score around 59'000 while it only needs 33'500 for the 3 stars. (I did a 36 combo).
To conclude, I would say good luck for everyone willing to complete this game as it was fun at the beginning, but a pain in the ass in the end.
Oh, and for those asking, I checked my stats...I only have under 4 hours of game time, so this game is really fast, you only need to wait to replenish your energy, that's what is boring in this kind of game..
Hope this guide will help you :)