There are a few things to consider when comparing the blacktop and Silvertop 4AGE engines. The first is power output. The Silvertop engine is rated at 165 hp, while the blacktop engine is rated at 185 hp. So, in terms of power output, the blacktop engine is better.
The second thing to consider is reliability. The Silvertop engine has a reputation for being more reliable than the blacktop engine. This is likely due to the fact that the Silvertop engine was designed for use in Toyota's Corolla GT-S, which was a very demanding application. The blacktop engine, on the other hand, was designed for use in the Toyota MR2, which wasn't as demanding. So, in terms of reliability, the Silvertop engine is probably better.
The third thing to consider is price. The Silvertop engine tends to be more expensive than the blacktop engine because it's rarer and more sought after by enthusiasts. So, if price isn't an issue, then the Silvertop 4AGE would be the better choice.