Wondering if it is possible to fit standard 4 pots from the 1999 all round front and back on my 1998?, and would they go straight on without modification, also is this a worth while mod?.

 

I think they'd go on the front without problems. IMHO it would be a complete waste of time and effort sticking 4-pots on the back.

If you want much better braking than that then go for some AP's on the front and go for a better compound brake pad on the rear. You could fit some rear 2-pot calipers from an STI, but I think you need to swap some of the axle components too.

Stefan