Yes, Road & Track are linear only.
Bilstein B16 springs are rumored as:
B16 PSS10 Golf 5:
VA: E4-FD1-Y704A00 > progressive; rate from 32.8 N/mm to 43.4 N/mm; 39 N/mm static
HA: E4-FD1-Y754A00 > progressive; rate from 33.0 N/mm to 50.1 N/mm; 50 N/mm static
R32 B16: (very) slightly stiffer.
Conclusion:
Öhlins R&T springs form a compromise between most street coilovers and clubsports. As
these are linear 60 mm dia standard, it'd be easy to replace them with the rate you want.