I am currently running a set of 7x16 audi alloys on my fab vrs using 205 45 16 tyres. I do have 2 new 195 45 16 tyres in the garage. Will it be ok to use these on the front or rear or do I need to stick with the 205's??

There will be a 0.5mph difference with those wheels at 30mph.

They could cause ABS to kick in early but very much doubt you have any problems at all.

Put them on the back

Here's a USEFUL SITE for such comparisons since it also gives allowable rim widths