Tri Pacers are great planes, however there are a few things to watch out for:
I recall ad AD for corrocsion in the weld joint in the fuselage frame, which is about where the pilot's left elbow would be. Big job to fix if damage found there. I don't recall if it is a recurring AD, but certainly worth understanding.
I recently posted the following on another thread. This situation might not be so critical for the Tri Pacer, as companies such as Univair might offer some support in the aftermarket. None the less, for what is it worth...
"As much as I really like Piper products, while undertaking the approval of a repair on a late 70"s Piper twin, I have encountered an alarming situation. Critical left and right primary structure parts, which are very simple single aluminum pieces, were found to be corroded, and not airworthy. Piper no longer makes available replacements for these parts, and is unwilling to support the field repair of the aircraft (and I have the email from Piper to prove it). In the absence of approved replacement parts, or aftermarket parts (which do not exist), the only option is a very expensive engineering and manufacturing exercise to repair the aircraft. This does not offer an assurance that the aircraft will ever return to the air - this could be the end for this particular aircraft. (Added to that, is the fact that this part is the subject of a Piper Service Bulleting for cracking, which would also require replacement!)
I don't know which aircraft Piper still supports, but the talk I had with their Tech Support person suggests that older aircraft made by Piper are not favoured for this support.
Before I bought a Piper, I'd be having a very thorough prepurchase inspection completed, with a real eye for corrosion, and the possible future need for replacement parts - they just might not be available!
It's long been known that aircraft manuafacturer's are not completely keen on their "legacy" aircraft remaining in service indefinately. It's hard for them to come right out and try to ground the aircraft, but it's much more easy and subtle to just stop making replacement parts available...
I love older aircraft, but it's time for prospective owners to do their homework!"