180's were never naturally aspirated from Nissan as far as I know. And an R34 for 6k might be pushing it. R32's in N/A form are also fairly rare, hence a higher price.
Asking for one of these for around 6k isn't really that feasible. Try 8-9k.
If you have 6k and want a P-Plate legal car, get a Mazda 3.
My 2c.