First off is it an 06 or an 07? The 07's had a tsb for the clutch, so check to see if they got that taken care of.
There is also a tsb I just got in the mail which warranties excess smoke coming out of the tailpipe from that notorious oil leak. But they are covering up to 70k miles, and will either replace the seals or the whole turbocharger.
I own a speed 6 and I swear I will probably never get rid of it. It's semi rare, looks good, got more than enough power, and the awd kicks ass. I live in minnesota and the ms6 carves through snow better than most trucks. I have owneed it for about 2 years now and the only problem i've had was a power steering leak (which I don't think is common). I put a SURE sri intake, turbosmart bpv, catback exhaust with dp, and SURE short shift plate with new shift bushings, and they give me more than enough go. But if I could afford to shell out 400 bucks for an AP I totally would. My girlfriend loves the car to. It feels safe and refined when you want it to, and like a sports car when you are feeling frisky. It's comfortable, easy to drive (minus the on/off switch clutch), and easy to maintain. For 43k miles I feel like you could get it for less than $17k I paid that for mine and it only had 29k miles on it. So I'd haggle em' down. Especially since it's alrady got mods on it. That's about all I can think to say about it. I say go for it!