Nissan STAGEA 260RS AUTECH VERSION '98 I think qualifies as a Sleeper.
I found the Honda Odyssey is a sleeper drift car lol. No one ever expects a mini-van to slide right next to them.
But, Sideways is sideways. Atleast it isn't the dime a dozen Silvia. I set mine up with 90% power to rear wheel the put the front Diff to all 5's and the front end does next to nothing for it's cornering or sliding. I do different and the Odyssey is very Different.
Edit: Just for the record I have alot of respect for Silvia's and all of the "drift missle" cars available, I just got tired of going into a room and seeing 15 identical cars. So I started by painting my MK3 Lava Orange pearl instead of the usual Black, Pink, Green and what not. I ended up with a Yellow Odyssey with Green wheels that I affectionately call "not quite ripe"
The Nissan Stagea 260RS Autech is acually a wagon Nissan Skyline BNCR33 or R33 GT-R.
I forgot which one but one of the two Stagea's it is but one of them in GT5 uses an entire GT-R Drivetrain and it is a monster.
Don't really know if it'd be considered a sleeper anymore since most people expect its power on take off, but the HPA R32 Stage II takes off quickly.
HPA R32 is a Built tuner car, anything but a sleeper. We have to take into account that the cars in GT5 have been around for years in various GT tittles, so, no car really can be a sleeper because cars like the 260RS are exposed. However the majority that are not as obsessed as some of us are with GT5 will have no clue what the 260RS is and its quite possible the best "Sleeper" car in the game.
Well I only considered it one since I haven't seen many people use it and didn't expect that it could possibly compete with GT-Rs.
Sleepers must be defined as an unassuming, grocery-getter looking car which only enthusiasts in the know would recognize as a capable road carving or stoplight weapon.
Like a Big Station Wagon maybe? lol
Ask anybody in America NOT into GT what a STAGIA 260RS is....
Even some people playing GT5 who are aware of the car are not sure of the name of it.
I saw your post and agree that the STAGEA qualifies. That said, there aren't many vehicles in GT5 which do.