A good way to start the game is to complete them time trials and get the panoz to win all the sunday cup races etc.
Then get golds on all the licenses and you have quite a garage... damn have to try that , what cars do you need to buy to complete GT3 keeping the number of purchased cars as low possible...
Ok let's see first you have the panoz for completing time trials
then you get golds on licenses and get this:
Mazda MX-5 Miata LS
Mazda RX8
Nissan Z Concept Car
Aston Martin Vanquish
Dodge Viper GTSR Concept Car
Subaru Impreza Rally Car Prototype
quite good right now you haven't even completed a single race in the Sim mode and have 7 quite nice cars (awww maybe excluding the miata)...
ok so after the first races (sunday and clubman , piece of cake) you get trueno and another miata
Then we can have some fun on the begginer league FR cup with aston martin or viper (yeah all cars expect impreza are rwd but those are fun) win a silvia 1800
then take the impreza for the 4WD challenge and win the Suzuki alto thing , then you take it for the Lightweight K-Cup and get the mini...
So right now we're with:
Panoz
Mazda MX-5 Miata LS
Mazda RX8
Nissan Z Concept Car
Aston Martin Vanquish
Dodge Viper GTSR Concept Car
Subaru Impreza Rally Car Prototype
Mazda MX-5 Miata
Toyota sprinter Trueno GT-Apex (AE86 Type I)
Silvia K's 1800
Suzki alto works suzuki sports limited
Mini cooper 1.3i
Ok then take the viper for the stars&stripes and win Camaro SS
Then we can win another miata in spider/roadster cup with one of our miatas , then take the miata once again to win the 80s sport car cup (i think it applies for it , to lazy to check)
then we take the NA sports and win the Del Sol , so we can tune it up and take it back to the FF cup to win a Vitz , and take the vitz to the vitz cup to win another vitz (doh)
Ok , for now:
Panoz
Mazda MX-5 Miata LS
Mazda RX8
Nissan Z Concept Car
Aston Martin Vanquish
Dodge Viper GTSR Concept Car
Subaru Impreza Rally Car Prototype
Mazda MX-5 Miata
Toyota sprinter Trueno GT-Apex (AE86 Type I)
Silvia K's 1800
Suzki alto works suzuki sports limited
Mini cooper 1.3i
Chevrolet Camaro SS
Mazda Mx-5 Miata 1.8 RS
Honda CRX del sol SiR
(Toyota Vitz RS 1.5)x2
Then win the turbo sports ang get the daihatsu , after that take on the GT world championship , save after the race before the last race and make sure you win the mitsubishi evolution , then take it for the evolution meeting...
Here's the list again:
Panoz
Mazda MX-5 Miata LS
Mazda RX8
Nissan Z Concept Car
Aston Martin Vanquish
Dodge Viper GTSR Concept Car
Subaru Impreza Rally Car Prototype
Mazda MX-5 Miata
Toyota sprinter Trueno GT-Apex (AE86 Type I)
Silvia K's 1800
Suzki alto works suzuki sports limited
Mini cooper 1.3i
Chevrolet Camaro SS
Mazda Mx-5 Miata 1.8 RS
Honda CRX del sol SiR
(Toyota Vitz RS 1.5) x2
Daihatsu Mira Tr XX Avantazo R
Mitsubishi Lancer evolution VI GSR
Mitsubishi Lancer evolution IV GSR
Now we move to the amateur league to obtain more cars...
First off the japanese championship i think we might get the fto using the "save trick" because it might be handy for the FF races , not like the Vitz or honda...
Then take the american championship , win the audi TT , get back to beginner and win the TT tourist throphy to win another TT , and win it in the amateur league to get the S4.... Then go to european championship and win the R34 GTR VspecII for the red emblem races...
Then go to GT world championship , win the GT-one road car , and maybe also the racing silvia if you like to...
List:
Panoz
Mazda MX-5 Miata LS
Mazda RX8
Nissan Z Concept Car
Aston Martin Vanquish
Dodge Viper GTSR Concept Car
Subaru Impreza Rally Car Prototype
Mazda MX-5 Miata
Toyota sprinter Trueno GT-Apex (AE86 Type I)
Silvia K's 1800
Suzki alto works suzuki sports limited
Mini cooper 1.3i
Chevrolet Camaro SS
Mazda Mx-5 Miata 1.8 RS
Honda CRX del sol SiR
(Toyota Vitz RS 1.5) x2
Daihatsu Mira Tr XX Avantazo R
Mitsubishi Lancer evolution VI GSR
Mitsubishi Lancer evolution IV GSR
Mitsubishi FTO GP version R
(Audi TT)x2
Audi S4
Nissan skyline R34 GTR VspecII
Toyota GT-one road car
Nissan C-West Razo Silvia
Then we have the german touring car challenge , win the cup beetle in there , go back to beginner league and win the Beetle RSI with it... then come TRD celica , Shigeno Trueno , NSX type-s Zero (in boulder opal blue , if you're lucky enough

) and mitsu lancer evo VII from FF,FR,MR and 4WD challenges...
Panoz
Mazda MX-5 Miata LS
Mazda RX8
Nissan Z Concept Car
Aston Martin Vanquish
Dodge Viper GTSR Concept Car
Subaru Impreza Rally Car Prototype
Mazda MX-5 Miata
Toyota sprinter Trueno GT-Apex (AE86 Type I)
Silvia K's 1800
Suzki alto works suzuki sports limited
Mini cooper 1.3i
Chevrolet Camaro SS
Mazda Mx-5 Miata 1.8 RS
Honda CRX del sol SiR
(Toyota Vitz RS 1.5) x2
Daihatsu Mira Tr XX Avantazo R
Mitsubishi Lancer evolution VI GSR
Mitsubishi Lancer evolution IV GSR
Mitsubishi FTO GP version R
(Audi TT)x2
Audi S4
Nissan skyline R34 GTR VspecII
Toyota GT-one road car
Nissan C-West Razo Silvia
Then win all the remaining races that you can enter , that way you can do everything besides silver arrow , altezza and type-r meeting....
Go to the pro league and keep winning all the races that any cars can enter with the panoz or souped-ep GT-one road car...
The key now is to win the FF challenge , get the spoon civic and win all the type-r meetings... Win the Zonda race car in all-japan championship , to win the italian avant garde...
Then get the ALtezza LM in Vitz championship and win all of the altezza series ... Get a formula car in the Dream car championship to win the formula series...
Now all we're missing is a TVR tuscan for the tuscan championship , a renault Clio for the clio championship , and any MB.... Go to the super speedway endurance to obtain the clio race car... then win the Clio series...
Then you can go win all the rally races and get the escudo for all golds....
But still you need any MB and a Tuscan to get 100%... It's a shame they could have made it that way so you could get 100% without buying anything... Oh you also get C5R and 787B for Getting 50% and 75%...
Buy a crappy MB and tune it so you win the silver arrow races
Now go buy tuscan , tune the hell out of it , finish the game and get the last F1 car...
It could have been easier and faster to make if you have taken the panoz and won all the racing events in high leagues and then with your super cars win the silly easy races but it's less fun i think