$400 with good compression and it's not a rust bucket?
Just buy it. Figure out details later.
Foolproof way to fix the issue is to just slap an MSD setup on there forget it.
This would also be great challenge fodder. Assuming the motor is healthy as he says, you could fairly easily get that thing in the 11s on a challenge budget.
Like Vigo said, though, i like the MX6 better. It's lighter. The Probe has a few tricks up it's sleeve that the MX6 doesn't, though. Flip up lights (AWESOME), bigger sway bars, and better instrumentation.
There's a few of us around with these motors.... Dan above, Me, and MNDSM recently bought an MX6 GT as well.
The motor is damn near unbreakable. I have 185k miles on mine, and it's swallowed all the boost i've cared to run on my MUCH larger than stock turbo without a single complaint. I do NOT baby this car. EVER. And it's fast. And still gets high 20s mpg combined.
Sadly... it's faster than my turbo miata, and i've got about 7x more money in the Miata.
Oh, and the transmissions and clutches last LONGER with bigger turbos. 