Rear tower, B4.1 Gen 2

[sheddy]

HI, Have built my B4.1 Gen 2 car now, Have noticed one problem.

When bolting the rear tower on, do I need to file a small part of the tower away below the mounting point or use a spacer on all four screws?

The tower does not sit flush on the lower mounts.

Also what Losi Big bore springs would be best to get for it?

Thanks, Dave