OK, I have an 89 525i with way too many problems ranging from rust to a leaky gas tank. I have spent about $8000 in upgrades and I would like to swap everything over to a new car. My question is can I swap my bilstein shocks and FK springs into an 89-91 535i or can they only be swapped into a 525i? If so, can I swap into a 92 or newer E34?

So what would you buy in my place? remember $$$ is a factor...
89-91 525i pro: everything can be swapped over con: slow
89-91 535i pro: faster than a 525i con: cant swap everything, $$ to buy
92+ 525i pro: M50 engine, newer car con: cant swap everything over, slow