day 694 to be pricise... B)
and they appear for one week in the garages gt time. If you have gone over 700 days, like me :) and aint got them....you can wait till day 1388 or every mutiple of 694
then theres 2 in garage 1 80's and 2 in garage 2 early 90's
they are....i think:
nisssan le mans thingy
mazda le mans thingy
a toyota gt1 (not sure)
other nissan thingy (not 100% on that either)
they aint as quick as the none second hand ones, because they have been ragged and dont apparantly tune up as high....and all can be bought for 8500000.cr or near to that
as for cheats...theres action replay ones that give you a bazillion credits and 100% completion...but thats pooright
i play this way too much...im going to sit in a corner and rock now (Y)