I love my 99 SLT - bought it for $1,000 had 210k on it.. did typical maintenance to it it hadn't had for a long time and it lasted 18,000 miles.. trans fried finally from a sticky caliper BUT everything else worked but the A/C - all that needs is a charge though
It's a 360/46RE (electronic 4 speed 727) trans 3.55 gears, has a superchips 87oct tune, CAI, and Magnaflow 3" catback
Things to look for in them-
1. Magnum 318/360's are known for cracked factory heads that are usually found by miss fires that won't go away - (mine has a cyl.5 miss that will not go away) it can sound like it's cam'd at idle- there is a company making brand new castings on eBay IIRC
2. There is a plate on the under side of the intake manifold that is known for filling the intake with oil - there are billet plates on eBay to fix it
3. The sure grips in the rear axles wear out fast - there are clutch kits to rebuild them
4. NEVER use the OD when driving below 40mph (has push button on gear shifter) if you do you will fry the OD band/clutches in the trans and it will not work
5. check the play in the rag joint going from the steering column to the steering box/rack - they're HARD to find OEM new..
I plan on doing a built trans, new top end, Hemifever SCT tune, and a small turbo mounted behind the front bumper on the passenger side