My Sons just been on with a oil change on his S2000 Turbo & he seems to think the Oil filter is the same as the Honda 
i.e. The Unipart GFE489 is listd both for the Elan & the S2000, He uses a HKS Hybrid Sports Oil Filter, so thinking if they are the same p/n the HKS will fit the Lotus?
The HKS advertising ......... says
In the interest of universal fitment, unit size has been standardized at φ68x65mm. Fitment bolt sizes are M20-1.5P and 3/4-16 UNF. Filtration performance JIS standard is 25μ whereas HKS is 20μ making the Filter compatible with most standard engine requirements.
★HKS Hybrid Sports Oil Filter has readdressed filter strength and overall structure to provide the oil flow that the engine requires and to pursue the HKS ideals in what is required from a sports oil filter.
★New HKS oil filter improves oil pressure drop and flow properties by approximately 30% compared to standard oil filters.
★Newly developed low resistance hybrid filter allows for low pressure loss. Engine response is improved by reducing the load on the engine.
■Features
■Construction
■Filter Life
Under normal usage, it is recommended that the filter is changed every 6,000 miles or 6 months. For Sports driving, the recommended distance is approximately 1/3 -1/2 of the previously mentioned figure (as the engine revolutions are several times that of normal driving). However, to maintain optimum low pressure loss properties, it is recommended to change the filter every 3000 miles when an oil change is performed.
The following link repeats the above with a bit of additional info.....
http://www.optionsauto.com/pdf/hks-oilfilter-app.pdf
