Tuning help needed for the RX-7 RZ

[GDPOVER9000]

Hello, everyone. I’ve just got my PS2 running again, and I popped in my dusty copy of GT3. So, as I’m going through a Beginner, I buy myself a Mazda RX-7 RZ. I have bought every part for it, but my tuning could use some help. Quite frankly, I’m looking for a car that can shred the German Touring Car Championships with ease, and I thought a maxed-out RX-7 RZ could do that, but so far no luck (not even close to winning a race in that series, to be honest). I also tried scouring the internet for tuning suggestions for my car, but I haven’t found one.

Any detailed tuning suggestions or car replacements for this series that you guys recommend? I have about 150k credits, also.

Thanks for your help/response in advance, everyone!