Does anyone have any ideas whether there are still any racing series using the 1990's supertouring rules today, i was just watching a video of the 1998 bathhurst 1000km supertouring, and cant help but think that touring car racing just isnt as exciting anymore

There's the Silverstone Classic coming up on 24-26 July. I know Jan "Flash" Nilsson from Sweden aim to be there in the Volvo S40 he raced from 1998 to 2002.

LMA Eurosaloons allows them in Class B, IIRC. They're probably permitted in Britcar, too.

As duke said LMA Eurosaloons is the place to race these cars, I think they're eligible for Britcar but are not competitive, the lowest class cuts off at around the S2000 level (our E46 touring car is currently outright champion ).