I wouldn't lower more than 40mm to be honest mate, it might start causing problems with rubbing arbs, ect...
http://www.venommotorsport.com/product_details.php?id=11299&manufacturer=Gmax&category=Suspension http://www.venommotorsport.com/product_details.php?id=12193&manufacturer=Gmax&category=Suspension
bought the gmax front shocks and i have the apex 35mm springs to use that i had already but not sure if they are too low and buy the 20mm ones for the r32