I don't think you have much clearance on engine side on an early A. I put a puller
on engine side and a pusher on the outside staggered to cover the core. My engine is only 300hp but the fans only come on when the car is stopped for a bit, stays cool
no problems. With a high HP setup as yours pick the best/biggest rad. and 2 high CFM fans. I have had bad experiences with fancy electronic fan controllers failing. I
now use simple capillary type ( one for each fan w relays) if one side fails you still
have backup.