When I was a noob, I was adament that the LX6 was the car for me, and that I would master it first.  This was the S1 equivalent of the FO8.  I tended to drive it on the easiest, fastest course (Fern Bay Green iirc).  Very soon afterwards a few 'masters of LFS' pointed out in no uncertain terms that I was crap at that car because I hadn't a clue how to drive.  They advised that I stick to the slower cars for a bit.  So I did.  I learnt a lot by avoiding the fastest car on the easiest course (of course, FO8 is faster and oval is easier, but you get my point).  When the MRT came out, I somehow specialised in it, and found the low power and quick responces to be brilliant, although the short wheelbase made catching mistakes difficult.
I think that if I had started LFS in the MRT then I wouldn't have been so good at it.  Learning to drive the slower cars might seem duller than 180mph, but I honestly think you learn more from it.
I don't see what you'll learn from buying LFS and spending a year on the oval.  You won't be learning proper oval techniques, as LFS currently isn't designed to simulate them - Nascar Racing 2003 is far far better for that at the moment.
And besides, ScarySquirrel, the starter of this thread, has been in touch with me and we've had a brief discussion.  I don't think he's ovalling much anymore, preferring to master other cars on proper tracks.  In short, he has now discovered LFS.