Need help with details on Calibra set up please!

[rosco1]

I have pulled my 1997 2.0l 16v Ecotec out of the shed and she is currently with the mechanic. Engine running nicely. Next stop the welder!
At the minute Im getting sorted for MOT.

It needs shocks, springs, full exhaust maybe manifold, brake discs, pads and lines all around as well as handbrake shoes fuel lines and ABS.
Mechanic is now waiting for me to order parts.

My query is:

How low can I lower front and back, and still fit 18"x 8" alloys without them rubbing on the arches? Can I get away with 60mm all around? I want to use the car on the track so I'm not too bothered about speed bumps and it ridding hard. In fact I will poly bush the whole thing at some point too when I've sorted a tuned engine.

I have already ordered a body kit which they say will be fine lowered 60mm. Ive picked the rims I want, but I just need to know about the ride height before I put the while order through.

Any advice greatly appreciated. Manta's were always my thing, this is my first Calibra build!