I have 374,000 on mine and it's still doing daily driver duty. The engine itself is probably the least likely part to give you trouble at 200,000. Many LT-1's did 400,000+ in police/taxi/civilian duties. As stated, maintenance is everything. The most likely areas of failure at 200,000 are 1)the transmission 2) Ball joints. 3. Waterpump. Opti-cap and rotor 3) cooling system issues, fans, radiator. I would want proof of a trans rebuild and have the suspension thoroughly checked for worn components and ball joints. Those would be my main concerns. The cooling system stuff, waterpump, cap and rotor are relatively cheap compared to the first 2.
'95 9c1, pcmperformance.com 93 tune, Dynomax Ultraflo catback, K & N box filter, LT4 KM, 160 stat, 3.08 Posi.